9972121525 has 6 divisors (see below), whose sum is σ = 12365430722. Its totient is φ = 7977697200.

The previous prime is 9972121517. The next prime is 9972121567. The reversal of 9972121525 is 5251212799.

It can be written as a sum of positive squares in 3 ways, for example, as 1403101764 + 8569019761 = 37458^2 + 92569^2 .

It is not a de Polignac number, because 9972121525 - 2³ = 9972121517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 199442406 + ... + 199442455.

Almost surely, 2^9972121525 is an apocalyptic number.

It is an amenable number.

9972121525 is a deficient number, since it is larger than the sum of its proper divisors (2393309197).

9972121525 is a wasteful number, since it uses less digits than its factorization.

9972121525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398884871 (or 398884866 counting only the distinct ones).

The product of its digits is 113400, while the sum is 43.

The square root of 9972121525 is about 99860.5103381712. The cubic root of 9972121525 is about 2152.4307481937.

The spelling of 9972121525 in words is "nine billion, nine hundred seventy-two million, one hundred twenty-one thousand, five hundred twenty-five".