21012523025 has 12 divisors (see below), whose sum is σ = 28059800412. Its totient is φ = 15516939840.

The previous prime is 21012523019. The next prime is 21012523031. The reversal of 21012523025 is 52032521012.

It is an interprime number because it is at equal distance from previous prime (21012523019) and next prime (21012523031).

It can be written as a sum of positive squares in 6 ways, for example, as 7097725504 + 13914797521 = 84248^2 + 117961^2 .

It is not a de Polignac number, because 21012523025 - 2⁶ = 21012522961 is a prime.

It is a super-2 number, since 2×21012523025² (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 11 ways as a sum of consecutive naturals, for example, 32326634 + ... + 32327283.

It is an arithmetic number, because the mean of its divisors is an integer number (2338316701).

Almost surely, 2^21012523025 is an apocalyptic number.

21012523025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21012523025 is a deficient number, since it is larger than the sum of its proper divisors (7047277387).

21012523025 is a wasteful number, since it uses less digits than its factorization.

21012523025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64653940 (or 64653935 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The spelling of 21012523025 in words is "twenty-one billion, twelve million, five hundred twenty-three thousand, twenty-five".