51681400 has 24 divisors (see below), whose sum is σ = 120159720. Its totient is φ = 20672480.

The previous prime is 51681379. The next prime is 51681401. The reversal of 51681400 is 418615.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51681401) 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 5 ways as a sum of consecutive naturals, for example, 129004 + ... + 129403.

It is an arithmetic number, because the mean of its divisors is an integer number (5006655).

Almost surely, 2^51681400 is an apocalyptic number.

51681400 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51681400 is an abundant number, since it is smaller than the sum of its proper divisors (68478320).

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

51681400 is a wasteful number, since it uses less digits than its factorization.

51681400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258423 (or 258414 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 51681400 is about 7188.9776741898. The cubic root of 51681400 is about 372.4872598979.

The spelling of 51681400 in words is "fifty-one million, six hundred eighty-one thousand, four hundred".