51981556 has 24 divisors (see below), whose sum is σ = 99459360. Its totient is φ = 23575200.

The previous prime is 51981533. The next prime is 51981557. The reversal of 51981556 is 65518915.

51981556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×51981556² = 5404164328362272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51981557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24090 + ... + 26158.

It is an arithmetic number, because the mean of its divisors is an integer number (4144140).

Almost surely, 2^51981556 is an apocalyptic number.

It is an amenable number.

51981556 is a deficient number, since it is larger than the sum of its proper divisors (47477804).

51981556 is a wasteful number, since it uses less digits than its factorization.

51981556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2655 (or 2653 counting only the distinct ones).

The product of its digits is 54000, while the sum is 40.

The square root of 51981556 is about 7209.8235762049. The cubic root of 51981556 is about 373.2069806967.

The spelling of 51981556 in words is "fifty-one million, nine hundred eighty-one thousand, five hundred fifty-six".