21307686800625 has 45 divisors (see below), whose sum is σ = 38460526067821. Its totient is φ = 11363914986000.

The previous prime is 21307686800623. The next prime is 21307686800641. The reversal of 21307686800625 is 52600868670312.

The square root of 21307686800625 is 4616025.

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

21307686800625 is a `hidden beast` number, since 2 + 1 + 3 + 0 + 7 + 6 + 8 + 6 + 8 + 0 + 0 + 625 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1670522645169 + 19637164155456 = 1292487^2 + 4431384^2 .

It is a tau number, because it is divible by the number of its divisors (45).

It is not a de Polignac number, because 21307686800625 - 2¹ = 21307686800623 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21307686800623) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 346171102 + ... + 346232648.

Almost surely, 2^{21307686800625} is an apocalyptic number.

21307686800625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21307686800625 is the 4616025-th square number.

21307686800625 is the 2308013-rd centered octagonal number.

It is an amenable number.

21307686800625 is a deficient number, since it is larger than the sum of its proper divisors (17152839267196).

21307686800625 is an frugal number, since it uses more digits than its factorization.

21307686800625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123120 (or 61555 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 21307686800625 in words is "twenty-one trillion, three hundred seven billion, six hundred eighty-six million, eight hundred thousand, six hundred twenty-five".