21757725025 has 9 divisors (see below), whose sum is σ = 26980493593. Its totient is φ = 17405590000.

The previous prime is 21757725013. The next prime is 21757725053. The reversal of 21757725025 is 52052775712.

The square root of 21757725025 is 147505.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1304148769 + 20453576256 = 36113^2 + 143016^2 .

It is not a de Polignac number, because 21757725025 - 2³¹ = 19610241377 is a prime.

It is a super-2 number, since 2×21757725025² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 722775 + ... + 752275.

Almost surely, 2^21757725025 is an apocalyptic number.

21757725025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21757725025 is the 147505-th square number.

21757725025 is the 73753-rd centered octagonal number.

It is an amenable number.

21757725025 is a deficient number, since it is larger than the sum of its proper divisors (5222768568).

21757725025 is an frugal number, since it uses more digits than its factorization.

21757725025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59012 (or 29506 counting only the distinct ones).

The product of its (nonzero) digits is 343000, while the sum is 43.

The spelling of 21757725025 in words is "twenty-one billion, seven hundred fifty-seven million, seven hundred twenty-five thousand, twenty-five".