21471920089 has 15 divisors (see below), whose sum is σ = 22529244927. Its totient is φ = 20464212648.

The previous prime is 21471920069. The next prime is 21471920101. The reversal of 21471920089 is 98002917412.

It is a happy number.

The square root of 21471920089 is 146533.

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

It can be written as a sum of positive squares in only one way, i.e., 3700897225 + 17771022864 = 60835^2 + 133308^2 .

It is not a de Polignac number, because 21471920089 - 2¹⁵ = 21471887321 is a prime.

It is a super-2 number, since 2×21471920089² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21471920009) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 77515819 + ... + 77516095.

Almost surely, 2^21471920089 is an apocalyptic number.

21471920089 is the 146533-rd square number.

21471920089 is the 73267-th centered octagonal number.

It is an amenable number.

21471920089 is a deficient number, since it is larger than the sum of its proper divisors (1057324838).

21471920089 is an frugal number, since it uses more digits than its factorization.

21471920089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646 (or 300 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 43.

The spelling of 21471920089 in words is "twenty-one billion, four hundred seventy-one million, nine hundred twenty thousand, eighty-nine".