51517881 has 6 divisors (see below), whose sum is σ = 74414730. Its totient is φ = 34345248.

The previous prime is 51517867. The next prime is 51517883. The reversal of 51517881 is 18871515.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 29811600 + 21706281 = 5460^2 + 4659^2 .

It is not a de Polignac number, because 51517881 - 2¹⁴ = 51501497 is a prime.

It is a super-2 number, since 2×51517881² = 5308184125460322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51517883) 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, 2862096 + ... + 2862113.

It is an arithmetic number, because the mean of its divisors is an integer number (12402455).

Almost surely, 2^51517881 is an apocalyptic number.

It is an amenable number.

51517881 is a deficient number, since it is larger than the sum of its proper divisors (22896849).

51517881 is a wasteful number, since it uses less digits than its factorization.

51517881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5724215 (or 5724212 counting only the distinct ones).

The product of its digits is 11200, while the sum is 36.

The square root of 51517881 is about 7177.5957673862. The cubic root of 51517881 is about 372.0939972318.

The spelling of 51517881 in words is "fifty-one million, five hundred seventeen thousand, eight hundred eighty-one".