20521995025 has 27 divisors (see below), whose sum is σ = 29609164881. Its totient is φ = 14068787040.

The previous prime is 20521995017. The next prime is 20521995037. The reversal of 20521995025 is 52059912502.

The square root of 20521995025 is 143255.

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 1047234321 + 19474760704 = 32361^2 + 139552^2 .

It is not a de Polignac number, because 20521995025 - 2³ = 20521995017 is a prime.

It is a super-2 number, since 2×20521995025² (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 26 ways as a sum of consecutive naturals, for example, 5011879 + ... + 5015971.

Almost surely, 2^20521995025 is an apocalyptic number.

20521995025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20521995025 is the 143255-th square number.

20521995025 is the 71628-th centered octagonal number.

It is an amenable number.

20521995025 is a deficient number, since it is larger than the sum of its proper divisors (9087169856).

20521995025 is an frugal number, since it uses more digits than its factorization.

20521995025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8210 (or 4105 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 40.

The spelling of 20521995025 in words is "twenty billion, five hundred twenty-one million, nine hundred ninety-five thousand, twenty-five".