20506904 has 32 divisors (see below), whose sum is σ = 42120000. Its totient is φ = 9282720.

The previous prime is 20506897. The next prime is 20506921. The reversal of 20506904 is 40960502.

It is a super-2 number, since 2×20506904² = 841066223330432, which contains 22 as substring.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 40847 + ... + 41345.

It is an arithmetic number, because the mean of its divisors is an integer number (1316250).

Almost surely, 2^20506904 is an apocalyptic number.

It is an amenable number.

20506904 is an abundant number, since it is smaller than the sum of its proper divisors (21613096).

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

20506904 is a wasteful number, since it uses less digits than its factorization.

20506904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983 (or 979 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20506904 is about 4528.4549241436. The cubic root of 20506904 is about 273.7159042347.

The spelling of 20506904 in words is "twenty million, five hundred six thousand, nine hundred four".