21230231 has 4 divisors (see below), whose sum is σ = 23160264. Its totient is φ = 19300200.

The previous prime is 21230227. The next prime is 21230243. The reversal of 21230231 is 13203212.

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 21230231 - 2² = 21230227 is a prime.

It is a super-2 number, since 2×21230231² = 901445416626722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230431) 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, 965000 + ... + 965021.

It is an arithmetic number, because the mean of its divisors is an integer number (5790066).

Almost surely, 2^21230231 is an apocalyptic number.

21230231 is a deficient number, since it is larger than the sum of its proper divisors (1930033).

21230231 is a wasteful number, since it uses less digits than its factorization.

21230231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930032.

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

The square root of 21230231 is about 4607.6274806021. The cubic root of 21230231 is about 276.8969932440.

Adding to 21230231 its reverse (13203212), we get a palindrome (34433443).

The spelling of 21230231 in words is "twenty-one million, two hundred thirty thousand, two hundred thirty-one".