21659017905625 has 15 divisors (see below), whose sum is σ = 27065254164267. Its totient is φ = 17327121246000.

The previous prime is 21659017905619. The next prime is 21659017905631. The reversal of 21659017905625 is 52650971095612.

It is a happy number.

The square root of 21659017905625 is 4653925.

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 (21659017905619) and next prime (21659017905631).

It can be written as a sum of positive squares in 7 ways, for example, as 4931539579849 + 16727478325776 = 2220707^2 + 4089924^2 .

It is not a de Polignac number, because 21659017905625 - 2¹⁷ = 21659017774553 is a prime.

It is a super-2 number, since 2×21659017905625² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21659017905625.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 116255047 + ... + 116441203.

Almost surely, 2^{21659017905625} is an apocalyptic number.

21659017905625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21659017905625 is the 4653925-th square number.

21659017905625 is the 2326963-rd centered octagonal number.

It is an amenable number.

21659017905625 is a deficient number, since it is larger than the sum of its proper divisors (5406236258642).

21659017905625 is an frugal number, since it uses more digits than its factorization.

21659017905625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372334 (or 186162 counting only the distinct ones).

The product of its (nonzero) digits is 10206000, while the sum is 58.

The spelling of 21659017905625 in words is "twenty-one trillion, six hundred fifty-nine billion, seventeen million, nine hundred five thousand, six hundred twenty-five".