21757047158025 has 81 divisors (see below), whose sum is σ = 39251390617621. Its totient is φ = 11520358207680.

The previous prime is 21757047158023. The next prime is 21757047158057. The reversal of 21757047158025 is 52085174075712.

The square root of 21757047158025 is 4664445.

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

21757047158025 is a `hidden beast` number, since 2 + 1 + 7 + 5 + 70 + 471 + 5 + 80 + 25 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6493460843529 + 15263586314496 = 2548227^2 + 3906864^2 .

It is not a de Polignac number, because 21757047158025 - 2¹ = 21757047158023 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21757047158023) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 10425033532 + ... + 10425035618.

Almost surely, 2^{21757047158025} is an apocalyptic number.

21757047158025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21757047158025 is the 4664445-th square number.

21757047158025 is the 2332223-rd centered octagonal number.

It is an amenable number.

21757047158025 is a deficient number, since it is larger than the sum of its proper divisors (17494343459596).

21757047158025 is an frugal number, since it uses more digits than its factorization.

21757047158025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4488 (or 2244 counting only the distinct ones).

The product of its (nonzero) digits is 5488000, while the sum is 54.

The spelling of 21757047158025 in words is "twenty-one trillion, seven hundred fifty-seven billion, forty-seven million, one hundred fifty-eight thousand, twenty-five".