21305364 has 48 divisors (see below), whose sum is σ = 51226560. Its totient is φ = 6888960.

The previous prime is 21305357. The next prime is 21305399. The reversal of 21305364 is 46350312.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88284 + ... + 88524.

It is an arithmetic number, because the mean of its divisors is an integer number (1067220).

Almost surely, 2^21305364 is an apocalyptic number.

It is an amenable number.

21305364 is an abundant number, since it is smaller than the sum of its proper divisors (29921196).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21305364 is a wasteful number, since it uses less digits than its factorization.

21305364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 21305364 is about 4615.7733913181. The cubic root of 21305364 is about 277.2232514036.

Adding to 21305364 its reverse (46350312), we get a palindrome (67655676).

The spelling of 21305364 in words is "twenty-one million, three hundred five thousand, three hundred sixty-four".