51781688 has 64 divisors (see below), whose sum is σ = 119750400. Its totient is φ = 20494080.

The previous prime is 51781673. The next prime is 51781703. The reversal of 51781688 is 88618715.

It is an interprime number because it is at equal distance from previous prime (51781673) and next prime (51781703).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43031 + ... + 44217.

It is an arithmetic number, because the mean of its divisors is an integer number (1871100).

Almost surely, 2^51781688 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 51781688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59875200).

51781688 is an abundant number, since it is smaller than the sum of its proper divisors (67968712).

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

51781688 is a wasteful number, since it uses less digits than its factorization.

51781688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260 (or 1256 counting only the distinct ones).

The product of its digits is 107520, while the sum is 44.

The square root of 51781688 is about 7195.9494161646. The cubic root of 51781688 is about 372.7280419792.

The spelling of 51781688 in words is "fifty-one million, seven hundred eighty-one thousand, six hundred eighty-eight".