51690816 has 84 divisors (see below), whose sum is σ = 151680672. Its totient is φ = 16821504.

The previous prime is 51690797. The next prime is 51690839. The reversal of 51690816 is 61809615.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23725 + ... + 25811.

Almost surely, 2^51690816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51690816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75840336).

51690816 is an abundant number, since it is smaller than the sum of its proper divisors (99989856).

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

51690816 is a wasteful number, since it uses less digits than its factorization.

51690816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2148 (or 2135 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 51690816 is about 7189.6325358115. The cubic root of 51690816 is about 372.5098800737.

The spelling of 51690816 in words is "fifty-one million, six hundred ninety thousand, eight hundred sixteen".