20631928 has 8 divisors (see below), whose sum is σ = 38684880. Its totient is φ = 10315960.

The previous prime is 20631911. The next prime is 20631937. The reversal of 20631928 is 82913602.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 20631928.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1289488 + ... + 1289503.

It is an arithmetic number, because the mean of its divisors is an integer number (4835610).

Almost surely, 2^20631928 is an apocalyptic number.

It is an amenable number.

20631928 is a deficient number, since it is larger than the sum of its proper divisors (18052952).

20631928 is a wasteful number, since it uses less digits than its factorization.

20631928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2578997 (or 2578993 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 20631928 is about 4542.2382148012. The cubic root of 20631928 is about 274.2710302365.

The spelling of 20631928 in words is "twenty million, six hundred thirty-one thousand, nine hundred twenty-eight".