51561500 has 24 divisors (see below), whose sum is σ = 112611408. Its totient is φ = 20624400.

The previous prime is 51561479. The next prime is 51561511. The reversal of 51561500 is 516515.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51062 + ... + 52061.

It is an arithmetic number, because the mean of its divisors is an integer number (4692142).

Almost surely, 2^51561500 is an apocalyptic number.

51561500 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51561500 is an abundant number, since it is smaller than the sum of its proper divisors (61049908).

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

51561500 is a wasteful number, since it uses less digits than its factorization.

51561500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103142 (or 103130 counting only the distinct ones).

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 51561500 is about 7180.6336767725. The cubic root of 51561500 is about 372.1989820725.

The spelling of 51561500 in words is "fifty-one million, five hundred sixty-one thousand, five hundred".