20305904 has 10 divisors (see below), whose sum is σ = 39342720. Its totient is φ = 10152944.

The previous prime is 20305897. The next prime is 20305907. The reversal of 20305904 is 40950302.

It is a self number, because there is not a number n which added to its sum of digits gives 20305904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20305907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 634544 + ... + 634575.

It is an arithmetic number, because the mean of its divisors is an integer number (3934272).

Almost surely, 2^20305904 is an apocalyptic number.

It is an amenable number.

20305904 is a deficient number, since it is larger than the sum of its proper divisors (19036816).

20305904 is a wasteful number, since it uses less digits than its factorization.

20305904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1269127 (or 1269121 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 20305904 is about 4506.2072744160. The cubic root of 20305904 is about 272.8186839168.

The spelling of 20305904 in words is "twenty million, three hundred five thousand, nine hundred four".