20757983 has 4 divisors (see below), whose sum is σ = 21660528. Its totient is φ = 19855440.

The previous prime is 20757967. The next prime is 20757991. The reversal of 20757983 is 38975702.

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

It is not a de Polignac number, because 20757983 - 2⁴ = 20757967 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 20757983.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20757953) 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, 451238 + ... + 451283.

It is an arithmetic number, because the mean of its divisors is an integer number (5415132).

Almost surely, 2^20757983 is an apocalyptic number.

20757983 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

20757983 is a deficient number, since it is larger than the sum of its proper divisors (902545).

20757983 is an equidigital number, since it uses as much as digits as its factorization.

20757983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902544.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 20757983 is about 4556.0929533977. The cubic root of 20757983 is about 274.8284682356.

The spelling of 20757983 in words is "twenty million, seven hundred fifty-seven thousand, nine hundred eighty-three".