20219904 has 72 divisors (see below), whose sum is σ = 58452030. Its totient is φ = 6733824.

The previous prime is 20219893. The next prime is 20219911. The reversal of 20219904 is 40991202.

It can be written as a sum of positive squares in only one way, i.e., 18662400 + 1557504 = 4320^2 + 1248^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17884 + ... + 18980.

Almost surely, 2^20219904 is an apocalyptic number.

20219904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20219904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29226015).

20219904 is an abundant number, since it is smaller than the sum of its proper divisors (38232126).

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

20219904 is a wasteful number, since it uses less digits than its factorization.

20219904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1125 (or 1102 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 20219904 is about 4496.6547565941. The cubic root of 20219904 is about 272.4329897233.

The spelling of 20219904 in words is "twenty million, two hundred nineteen thousand, nine hundred four".