51491916 has 48 divisors (see below), whose sum is σ = 152570880. Its totient is φ = 14711760.

The previous prime is 51491857. The next prime is 51491933. The reversal of 51491916 is 61919415.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 33300 + ... + 34811.

It is an arithmetic number, because the mean of its divisors is an integer number (3178560).

Almost surely, 2^51491916 is an apocalyptic number.

It is an amenable number.

51491916 is an abundant number, since it is smaller than the sum of its proper divisors (101078964).

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

51491916 is a wasteful number, since it uses less digits than its factorization.

51491916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68131 (or 68123 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 51491916 is about 7175.7867861301. The cubic root of 51491916 is about 372.0314749643.

The spelling of 51491916 in words is "fifty-one million, four hundred ninety-one thousand, nine hundred sixteen".