21320344 has 8 divisors (see below), whose sum is σ = 39975660. Its totient is φ = 10660168.

The previous prime is 21320323. The next prime is 21320401. The reversal of 21320344 is 44302312.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332514 + ... + 1332529.

Almost surely, 2^21320344 is an apocalyptic number.

It is an amenable number.

21320344 is a deficient number, since it is larger than the sum of its proper divisors (18655316).

21320344 is a wasteful number, since it uses less digits than its factorization.

21320344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2665049 (or 2665045 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21320344 is about 4617.3958028309. The cubic root of 21320344 is about 277.2882089325.

Adding to 21320344 its reverse (44302312), we get a palindrome (65622656).

The spelling of 21320344 in words is "twenty-one million, three hundred twenty thousand, three hundred forty-four".