20973990 has 16 divisors (see below), whose sum is σ = 50337648. Its totient is φ = 5593056.

The previous prime is 20973977. The next prime is 20974013. The reversal of 20973990 is 9937902.

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, 349537 + ... + 349596.

It is an arithmetic number, because the mean of its divisors is an integer number (3146103).

Almost surely, 2^20973990 is an apocalyptic number.

20973990 is an abundant number, since it is smaller than the sum of its proper divisors (29363658).

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

20973990 is a wasteful number, since it uses less digits than its factorization.

20973990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699143.

The product of its (nonzero) digits is 30618, while the sum is 39.

The square root of 20973990 is about 4579.7368920059. The cubic root of 20973990 is about 275.7784664243.

The spelling of 20973990 in words is "twenty million, nine hundred seventy-three thousand, nine hundred ninety".