51215428881 has 6 divisors (see below), whose sum is σ = 73977841730. Its totient is φ = 34143619248.

The previous prime is 51215428843. The next prime is 51215428883. The reversal of 51215428881 is 18882451215.

51215428881 is a `hidden beast` number, since 5 + 1 + 21 + 542 + 8 + 8 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 51010481025 + 204947856 = 225855^2 + 14316^2 .

It is not a de Polignac number, because 51215428881 - 2¹⁹ = 51214904593 is a prime.

It is a super-2 number, since 2×51215428881² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51215428883) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2845301596 + ... + 2845301613.

Almost surely, 2^51215428881 is an apocalyptic number.

It is an amenable number.

51215428881 is a deficient number, since it is larger than the sum of its proper divisors (22762412849).

51215428881 is a wasteful number, since it uses less digits than its factorization.

51215428881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5690603215 (or 5690603212 counting only the distinct ones).

The product of its digits is 204800, while the sum is 45.

The spelling of 51215428881 in words is "fifty-one billion, two hundred fifteen million, four hundred twenty-eight thousand, eight hundred eighty-one".