51680664 has 144 divisors (see below), whose sum is σ = 166648560. Its totient is φ = 14169600.

The previous prime is 51680653. The next prime is 51680669. The reversal of 51680664 is 46608615.

51680664 is a `hidden beast` number, since 516 + 80 + 6 + 64 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51680669) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 847194 + ... + 847254.

Almost surely, 2^51680664 is an apocalyptic number.

51680664 is the 3843-rd nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51680664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83324280).

51680664 is an abundant number, since it is smaller than the sum of its proper divisors (114967896).

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

51680664 is a wasteful number, since it uses less digits than its factorization.

51680664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 51680664 is about 7188.9264845316. The cubic root of 51680664 is about 372.4854916800.

The spelling of 51680664 in words is "fifty-one million, six hundred eighty thousand, six hundred sixty-four".