51688778 has 32 divisors (see below), whose sum is σ = 84907200. Its totient is φ = 23514624.

The previous prime is 51688771. The next prime is 51688807. The reversal of 51688778 is 87788615.

It is a super-2 number, since 2×51688778² = 5343459542266568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51688771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136193 + ... + 136571.

It is an arithmetic number, because the mean of its divisors is an integer number (2653350).

Almost surely, 2^51688778 is an apocalyptic number.

51688778 is a deficient number, since it is larger than the sum of its proper divisors (33218422).

51688778 is a wasteful number, since it uses less digits than its factorization.

51688778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534.

The product of its digits is 752640, while the sum is 50.

The square root of 51688778 is about 7189.4908025534. The cubic root of 51688778 is about 372.5049843935.

The spelling of 51688778 in words is "fifty-one million, six hundred eighty-eight thousand, seven hundred seventy-eight".