20720983 has 4 divisors (see below), whose sum is σ = 20860200. Its totient is φ = 20581768.

The previous prime is 20720971. The next prime is 20721013. The reversal of 20720983 is 38902702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20720983 - 2⁵ = 20720951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69385 + ... + 69682.

It is an arithmetic number, because the mean of its divisors is an integer number (5215050).

Almost surely, 2^20720983 is an apocalyptic number.

20720983 is a deficient number, since it is larger than the sum of its proper divisors (139217).

20720983 is a wasteful number, since it uses less digits than its factorization.

20720983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139216.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 20720983 is about 4552.0306457668. The cubic root of 20720983 is about 274.6650820818.

The spelling of 20720983 in words is "twenty million, seven hundred twenty thousand, nine hundred eighty-three".