20639833 has 4 divisors (see below), whose sum is σ = 21726160. Its totient is φ = 19553508.

The previous prime is 20639807. The next prime is 20639837. The reversal of 20639833 is 33893602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20639833 - 2¹³ = 20631641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20639837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543135 + ... + 543172.

It is an arithmetic number, because the mean of its divisors is an integer number (5431540).

Almost surely, 2^20639833 is an apocalyptic number.

It is an amenable number.

20639833 is a deficient number, since it is larger than the sum of its proper divisors (1086327).

20639833 is a wasteful number, since it uses less digits than its factorization.

20639833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086326.

The product of its (nonzero) digits is 23328, while the sum is 34.

The square root of 20639833 is about 4543.1082971904. The cubic root of 20639833 is about 274.3060541996.

The spelling of 20639833 in words is "twenty million, six hundred thirty-nine thousand, eight hundred thirty-three".