21003255625 has 135 divisors (see below), whose sum is σ = 31665787923. Its totient is φ = 13912800000.

The previous prime is 21003255617. The next prime is 21003255631. The reversal of 21003255625 is 52655230012.

It is a happy number.

The square root of 21003255625 is 144925.

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

It can be written as a sum of positive squares in 7 ways, for example, as 10257030729 + 10746224896 = 101277^2 + 103664^2 .

It is not a de Polignac number, because 21003255625 - 2³ = 21003255617 is a prime.

It is a super-2 number, since 2×21003255625² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 677524360 + ... + 677524390.

Almost surely, 2^21003255625 is an apocalyptic number.

21003255625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21003255625 is the 144925-th square number.

21003255625 is the 72463-rd centered octagonal number.

It is an amenable number.

21003255625 is a deficient number, since it is larger than the sum of its proper divisors (10662532298).

21003255625 is an equidigital number, since it uses as much as digits as its factorization.

21003255625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 31.

Adding to 21003255625 its reverse (52655230012), we get a palindrome (73658485637).

The spelling of 21003255625 in words is "twenty-one billion, three million, two hundred fifty-five thousand, six hundred twenty-five".