51685550 has 24 divisors (see below), whose sum is σ = 109869456. Its totient is φ = 17720640.

The previous prime is 51685523. The next prime is 51685561. The reversal of 51685550 is 5558615.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 51685550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73487 + ... + 74186.

It is an arithmetic number, because the mean of its divisors is an integer number (4577894).

Almost surely, 2^51685550 is an apocalyptic number.

51685550 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

51685550 is an abundant number, since it is smaller than the sum of its proper divisors (58183906).

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

51685550 is a wasteful number, since it uses less digits than its factorization.

51685550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147692 (or 147687 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 35.

The square root of 51685550 is about 7189.2663047073. The cubic root of 51685550 is about 372.4972298339.

The spelling of 51685550 in words is "fifty-one million, six hundred eighty-five thousand, five hundred fifty".