51381851085 has 48 divisors (see below), whose sum is σ = 90520125696. Its totient is φ = 26958357504.

The previous prime is 51381851021. The next prime is 51381851173. The reversal of 51381851085 is 58015818315.

51381851085 is a `hidden beast` number, since 51 + 3 + 8 + 1 + 8 + 510 + 85 = 666.

It is not a de Polignac number, because 51381851085 - 2⁶ = 51381851021 is a prime.

It is a super-2 number, since 2×51381851085² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 51381851085.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 693712 + ... + 764198.

It is an arithmetic number, because the mean of its divisors is an integer number (1885835952).

Almost surely, 2^51381851085 is an apocalyptic number.

It is an amenable number.

51381851085 is a deficient number, since it is larger than the sum of its proper divisors (39138274611).

51381851085 is a wasteful number, since it uses less digits than its factorization.

51381851085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70762 (or 70759 counting only the distinct ones).

The product of its (nonzero) digits is 192000, while the sum is 45.

The spelling of 51381851085 in words is "fifty-one billion, three hundred eighty-one million, eight hundred fifty-one thousand, eighty-five".