20698021 has 4 divisors (see below), whose sum is σ = 20740000. Its totient is φ = 20656044.

The previous prime is 20698019. The next prime is 20698039. The reversal of 20698021 is 12089602.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 20698021 - 2¹ = 20698019 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 (20698081) 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, 20241 + ... + 21238.

It is an arithmetic number, because the mean of its divisors is an integer number (5185000).

Almost surely, 2^20698021 is an apocalyptic number.

It is an amenable number.

20698021 is a deficient number, since it is larger than the sum of its proper divisors (41979).

20698021 is an equidigital number, since it uses as much as digits as its factorization.

20698021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41978.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20698021 is about 4549.5077755731. The cubic root of 20698021 is about 274.5635876900.

The spelling of 20698021 in words is "twenty million, six hundred ninety-eight thousand, twenty-one".