51121125405 has 80 divisors (see below), whose sum is σ = 104802386304. Its totient is φ = 23353660800.

The previous prime is 51121125401. The next prime is 51121125463. The reversal of 51121125405 is 50452112115.

It is a happy number.

51121125405 is a `hidden beast` number, since 5 + 1 + 1 + 2 + 112 + 540 + 5 = 666.

It is not a de Polignac number, because 51121125405 - 2² = 51121125401 is a prime.

It is a super-2 number, since 2×51121125405² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51121125401) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 4794330 + ... + 4804980.

Almost surely, 2^51121125405 is an apocalyptic number.

It is an amenable number.

51121125405 is an abundant number, since it is smaller than the sum of its proper divisors (53681260899).

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

51121125405 is a wasteful number, since it uses less digits than its factorization.

51121125405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12368 (or 12359 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The spelling of 51121125405 in words is "fifty-one billion, one hundred twenty-one million, one hundred twenty-five thousand, four hundred five".