20305990 has 16 divisors (see below), whose sum is σ = 38701152. Its totient is φ = 7644544.

The previous prime is 20305981. The next prime is 20306017. The reversal of 20305990 is 9950302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59554 + ... + 59893.

It is an arithmetic number, because the mean of its divisors is an integer number (2418822).

Almost surely, 2^20305990 is an apocalyptic number.

20305990 is a deficient number, since it is larger than the sum of its proper divisors (18395162).

20305990 is a wasteful number, since it uses less digits than its factorization.

20305990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119471.

The product of its (nonzero) digits is 2430, while the sum is 28.

The square root of 20305990 is about 4506.2168167988. The cubic root of 20305990 is about 272.8190690654.

The spelling of 20305990 in words is "twenty million, three hundred five thousand, nine hundred ninety".