21958201489 has 9 divisors (see below), whose sum is σ = 25544420667. Its totient is φ = 18820426464.

The previous prime is 21958201477. The next prime is 21958201501. The reversal of 21958201489 is 98410285912.

The square root of 21958201489 is 148183.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (21958201477) and next prime (21958201501).

It can be written as a sum of positive squares in only one way, i.e., 21364791889 + 593409600 = 146167^2 + 24360^2 .

It is not a de Polignac number, because 21958201489 - 2⁵ = 21958201457 is a prime.

It is a super-2 number, since 2×21958201489² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21958201289) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1026697 + ... + 1047865.

It is an arithmetic number, because the mean of its divisors is an integer number (2838268963).

Almost surely, 2^21958201489 is an apocalyptic number.

21958201489 is the 148183-rd square number.

21958201489 is the 74092-nd centered octagonal number.

It is an amenable number.

21958201489 is a deficient number, since it is larger than the sum of its proper divisors (3586219178).

21958201489 is an frugal number, since it uses more digits than its factorization.

21958201489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42352 (or 21176 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 49.

Multiplying 21958201489 by its sum of digits (49), we get a square (1075951872961 = 1037281²).

21958201489 divided by its sum of digits (49) gives a square (448126561 = 21169²).

The spelling of 21958201489 in words is "twenty-one billion, nine hundred fifty-eight million, two hundred one thousand, four hundred eighty-nine".