20191904 has 12 divisors (see below), whose sum is σ = 39752874. Its totient is φ = 10095936.

The previous prime is 20191879. The next prime is 20191931. The reversal of 20191904 is 40919102.

It can be written as a sum of positive squares in only one way, i.e., 19891600 + 300304 = 4460^2 + 548^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315467 + ... + 315530.

Almost surely, 2^20191904 is an apocalyptic number.

It is an amenable number.

20191904 is a deficient number, since it is larger than the sum of its proper divisors (19560970).

20191904 is an equidigital number, since it uses as much as digits as its factorization.

20191904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631007 (or 630999 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 20191904 is about 4493.5402524068. The cubic root of 20191904 is about 272.3071789133.

The spelling of 20191904 in words is "twenty million, one hundred ninety-one thousand, nine hundred four".