51531879721 has 8 divisors (see below), whose sum is σ = 58897851264. Its totient is φ = 44166976800.

The previous prime is 51531879709. The next prime is 51531879727. The reversal of 51531879721 is 12797813515.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51531879721 - 2¹¹ = 51531877673 is a prime.

It is a super-2 number, since 2×51531879721² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51531879727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 161005 + ... + 359146.

It is an arithmetic number, because the mean of its divisors is an integer number (7362231408).

Almost surely, 2^51531879721 is an apocalyptic number.

It is an amenable number.

51531879721 is a deficient number, since it is larger than the sum of its proper divisors (7365971543).

51531879721 is a wasteful number, since it uses less digits than its factorization.

51531879721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534311.

The product of its digits is 529200, while the sum is 49.

The spelling of 51531879721 in words is "fifty-one billion, five hundred thirty-one million, eight hundred seventy-nine thousand, seven hundred twenty-one".