51661993572 has 36 divisors (see below), whose sum is σ = 149245759936. Its totient is φ = 14760569520.

The previous prime is 51661993517. The next prime is 51661993597. The reversal of 51661993572 is 27539916615.

51661993572 is a `hidden beast` number, since 5 + 1 + 6 + 61 + 9 + 9 + 3 + 572 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 102503704 + ... + 102504207.

Almost surely, 2^51661993572 is an apocalyptic number.

It is an amenable number.

51661993572 is an abundant number, since it is smaller than the sum of its proper divisors (97583766364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51661993572 is a wasteful number, since it uses less digits than its factorization.

51661993572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205007928 (or 205007923 counting only the distinct ones).

The product of its digits is 3061800, while the sum is 54.

The spelling of 51661993572 in words is "fifty-one billion, six hundred sixty-one million, nine hundred ninety-three thousand, five hundred seventy-two".