21323901 has 4 divisors (see below), whose sum is σ = 28431872. Its totient is φ = 14215932.

The previous prime is 21323893. The next prime is 21323941. The reversal of 21323901 is 10932312.

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 not a de Polignac number, because 21323901 - 2³ = 21323893 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 (21323941) 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, 3553981 + ... + 3553986.

It is an arithmetic number, because the mean of its divisors is an integer number (7107968).

Almost surely, 2^21323901 is an apocalyptic number.

It is an amenable number.

21323901 is a deficient number, since it is larger than the sum of its proper divisors (7107971).

21323901 is an equidigital number, since it uses as much as digits as its factorization.

21323901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7107970.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21323901 is about 4617.7809605914. The cubic root of 21323901 is about 277.3036286230.

The spelling of 21323901 in words is "twenty-one million, three hundred twenty-three thousand, nine hundred one".