51081907390920 has 512 divisors, whose sum is σ = 197367363072000. Its totient is φ = 11509856040960.

The previous prime is 51081907390897. The next prime is 51081907390931. The reversal of 51081907390920 is 2909370918015.

51081907390920 is a `hidden beast` number, since 5 + 1 + 0 + 81 + 90 + 7 + 390 + 92 + 0 = 666.

It is a super-2 number, since 2×51081907390920² (a number of 28 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1092147135 + ... + 1092193905.

It is an arithmetic number, because the mean of its divisors is an integer number (385483131000).

Almost surely, 2^{51081907390920} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51081907390920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98683681536000).

51081907390920 is an abundant number, since it is smaller than the sum of its proper divisors (146285455681080).

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

51081907390920 is a wasteful number, since it uses less digits than its factorization.

51081907390920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48850 (or 48840 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The spelling of 51081907390920 in words is "fifty-one trillion, eighty-one billion, nine hundred seven million, three hundred ninety thousand, nine hundred twenty".