51690990 has 32 divisors (see below), whose sum is σ = 133602336. Its totient is φ = 12723840.

The previous prime is 51690983. The next prime is 51691019. The reversal of 51690990 is 9909615.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65881 + ... + 66660.

It is an arithmetic number, because the mean of its divisors is an integer number (4175073).

Almost surely, 2^51690990 is an apocalyptic number.

51690990 is an abundant number, since it is smaller than the sum of its proper divisors (81911346).

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

51690990 is a wasteful number, since it uses less digits than its factorization.

51690990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132564.

The product of its (nonzero) digits is 21870, while the sum is 39.

The square root of 51690990 is about 7189.6446365589. The cubic root of 51690990 is about 372.5102980502.

The spelling of 51690990 in words is "fifty-one million, six hundred ninety thousand, nine hundred ninety".