20213231 has 4 divisors (see below), whose sum is σ = 20413464. Its totient is φ = 20013000.

The previous prime is 20213197. The next prime is 20213233. The reversal of 20213231 is 13231202.

It is a happy number.

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 20213231 - 2²² = 16018927 is a prime.

It is a super-2 number, since 2×20213231² = 817149414918722, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213233) 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, 99965 + ... + 100166.

It is an arithmetic number, because the mean of its divisors is an integer number (5103366).

Almost surely, 2^20213231 is an apocalyptic number.

20213231 is a deficient number, since it is larger than the sum of its proper divisors (200233).

20213231 is a wasteful number, since it uses less digits than its factorization.

20213231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200232.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 20213231 is about 4495.9126993304. The cubic root of 20213231 is about 272.4030168582.

Adding to 20213231 its reverse (13231202), we get a palindrome (33444433).

The spelling of 20213231 in words is "twenty million, two hundred thirteen thousand, two hundred thirty-one".