21810268489 has 9 divisors (see below), whose sum is σ = 22803321639. Its totient is φ = 20858746920.

The previous prime is 21810268433. The next prime is 21810268523. The reversal of 21810268489 is 98486201812.

The square root of 21810268489 is 147683.

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., 6039932089 + 15770336400 = 77717^2 + 125580^2 .

It is not a de Polignac number, because 21810268489 - 2¹⁷ = 21810137417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21810268429) 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, 3393499 + ... + 3399919.

Almost surely, 2^21810268489 is an apocalyptic number.

21810268489 is the 147683-rd square number.

21810268489 is the 73842-nd centered octagonal number.

It is an amenable number.

21810268489 is a deficient number, since it is larger than the sum of its proper divisors (993053150).

21810268489 is an frugal number, since it uses more digits than its factorization.

21810268489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12888 (or 6444 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 49.

Multiplying 21810268489 by its sum of digits (49), we get a square (1068703155961 = 1033781²).

The spelling of 21810268489 in words is "twenty-one billion, eight hundred ten million, two hundred sixty-eight thousand, four hundred eighty-nine".