21598711225 has 243 divisors, whose sum is σ = 37822566087. Its totient is φ = 12189864960.

The previous prime is 21598711217. The next prime is 21598711229. The reversal of 21598711225 is 52211789512.

The square root of 21598711225 is 146965.

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

It can be written as a sum of positive squares in 13 ways, for example, as 15729925561 + 5868785664 = 125419^2 + 76608^2 .

It is not a de Polignac number, because 21598711225 - 2³ = 21598711217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21598711229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 1136774266 + ... + 1136774284.

Almost surely, 2^21598711225 is an apocalyptic number.

21598711225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21598711225 is the 146965-th square number.

21598711225 is the 73483-rd centered octagonal number.

It is an amenable number.

21598711225 is a deficient number, since it is larger than the sum of its proper divisors (16223854862).

21598711225 is a wasteful number, since it uses less digits than its factorization.

21598711225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 61 counting only the distinct ones).

The product of its digits is 100800, while the sum is 43.

The spelling of 21598711225 in words is "twenty-one billion, five hundred ninety-eight million, seven hundred eleven thousand, two hundred twenty-five".