21537030025 has 45 divisors (see below), whose sum is σ = 31207148231. Its totient is φ = 14743594320.

The previous prime is 21537030001. The next prime is 21537030049. The reversal of 21537030025 is 52003073512.

The square root of 21537030025 is 146755.

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 (21537030001) and next prime (21537030049).

It can be written as a sum of positive squares in only one way, i.e., 7753330809 + 13783699216 = 88053^2 + 117404^2 .

It is not a de Polignac number, because 21537030025 - 2⁷ = 21537029897 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21537029975 and 21537030002.

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 44 ways as a sum of consecutive naturals, for example, 35954676 + ... + 35955274.

Almost surely, 2^21537030025 is an apocalyptic number.

21537030025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21537030025 is the 146755-th square number.

21537030025 is the 73378-th centered octagonal number.

It is an amenable number.

21537030025 is a deficient number, since it is larger than the sum of its proper divisors (9670118206).

21537030025 is an frugal number, since it uses more digits than its factorization.

21537030025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 28.

The spelling of 21537030025 in words is "twenty-one billion, five hundred thirty-seven million, thirty thousand, twenty-five".