51561750 has 32 divisors (see below), whose sum is σ = 128700000. Its totient is φ = 13749600.

The previous prime is 51561743. The next prime is 51561761. The reversal of 51561750 is 5716515.

It is a super-2 number, since 2×51561750² = 5317228126125000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 33625 + ... + 35124.

It is an arithmetic number, because the mean of its divisors is an integer number (4021875).

Almost surely, 2^51561750 is an apocalyptic number.

51561750 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

51561750 is an abundant number, since it is smaller than the sum of its proper divisors (77138250).

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

51561750 is a wasteful number, since it uses less digits than its factorization.

51561750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68769 (or 68759 counting only the distinct ones).

The product of its (nonzero) digits is 5250, while the sum is 30.

The square root of 51561750 is about 7180.6510846858. The cubic root of 51561750 is about 372.1995836169.

The spelling of 51561750 in words is "fifty-one million, five hundred sixty-one thousand, seven hundred fifty".