20973983 has 4 divisors (see below), whose sum is σ = 20992488. Its totient is φ = 20955480.

The previous prime is 20973977. The next prime is 20974013. The reversal of 20973983 is 38937902.

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 20973983 - 2¹² = 20969887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20973983.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20973913) 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, 7433 + ... + 9858.

It is an arithmetic number, because the mean of its divisors is an integer number (5248122).

Almost surely, 2^20973983 is an apocalyptic number.

20973983 is a deficient number, since it is larger than the sum of its proper divisors (18505).

20973983 is a wasteful number, since it uses less digits than its factorization.

20973983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18504.

The product of its (nonzero) digits is 81648, while the sum is 41.

The square root of 20973983 is about 4579.7361277698. The cubic root of 20973983 is about 275.7784357442.

The spelling of 20973983 in words is "twenty million, nine hundred seventy-three thousand, nine hundred eighty-three".