51556530 has 16 divisors (see below), whose sum is σ = 123735744. Its totient is φ = 13748400.

The previous prime is 51556523. The next prime is 51556541. The reversal of 51556530 is 3565515.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 1718551 = 51556530 / (5 + 1 + 5 + 5 + 6 + 5 + 3 + 0).

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 7 ways as a sum of consecutive naturals, for example, 859246 + ... + 859305.

It is an arithmetic number, because the mean of its divisors is an integer number (7733484).

Almost surely, 2^51556530 is an apocalyptic number.

51556530 is an abundant number, since it is smaller than the sum of its proper divisors (72179214).

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

51556530 is a wasteful number, since it uses less digits than its factorization.

51556530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1718561.

The product of its (nonzero) digits is 11250, while the sum is 30.

The square root of 51556530 is about 7180.2875986969. The cubic root of 51556530 is about 372.1870229662.

The spelling of 51556530 in words is "fifty-one million, five hundred fifty-six thousand, five hundred thirty".