70909831521 has 27 divisors (see below), whose sum is σ = 105312279891. Its totient is φ = 45976393584.

The previous prime is 70909831459. The next prime is 70909831541. The reversal of 70909831521 is 12513890907.

The square root of 70909831521 is 266289.

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

70909831521 is a `hidden beast` number, since 7 + 0 + 9 + 0 + 98 + 31 + 521 = 666.

It can be written as a sum of positive squares in only one way, i.e., 63451091025 + 7458740496 = 251895^2 + 86364^2 .

It is not a de Polignac number, because 70909831521 - 2⁷ = 70909831393 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (70909831541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 29556880 + ... + 29559278.

Almost surely, 2^70909831521 is an apocalyptic number.

70909831521 is the 266289-th square number.

70909831521 is the 133145-th centered octagonal number.

It is an amenable number.

70909831521 is a deficient number, since it is larger than the sum of its proper divisors (34402448370).

70909831521 is an frugal number, since it uses more digits than its factorization.

70909831521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4878 (or 2439 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The spelling of 70909831521 in words is "seventy billion, nine hundred nine million, eight hundred thirty-one thousand, five hundred twenty-one".