21308700625 has 15 divisors (see below), whose sum is σ = 26631913341. Its totient is φ = 17044041000.

The previous prime is 21308700601. The next prime is 21308700629. The reversal of 21308700625 is 52600780312.

It is a happy number.

The square root of 21308700625 is 145975.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1670602129 + 19638098496 = 40873^2 + 140136^2 .

It is not a de Polignac number, because 21308700625 - 2⁵ = 21308700593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21308700629) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 3646456 + ... + 3652294.

Almost surely, 2^21308700625 is an apocalyptic number.

21308700625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21308700625 is the 145975-th square number.

21308700625 is the 72988-th centered octagonal number.

It is an amenable number.

21308700625 is a deficient number, since it is larger than the sum of its proper divisors (5323212716).

21308700625 is an frugal number, since it uses more digits than its factorization.

21308700625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11698 (or 5844 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 34.

The spelling of 21308700625 in words is "twenty-one billion, three hundred eight million, seven hundred thousand, six hundred twenty-five".