21439364 has 6 divisors (see below), whose sum is σ = 37518894. Its totient is φ = 10719680.

The previous prime is 21439343. The next prime is 21439387. The reversal of 21439364 is 46393412.

It can be written as a sum of positive squares in only one way, i.e., 19360000 + 2079364 = 4400^2 + 1442^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21439364.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2679917 + ... + 2679924.

It is an arithmetic number, because the mean of its divisors is an integer number (6253149).

Almost surely, 2^21439364 is an apocalyptic number.

It is an amenable number.

21439364 is a deficient number, since it is larger than the sum of its proper divisors (16079530).

21439364 is a wasteful number, since it uses less digits than its factorization.

21439364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5359845 (or 5359843 counting only the distinct ones).

The product of its digits is 15552, while the sum is 32.

The square root of 21439364 is about 4630.2660830669. The cubic root of 21439364 is about 277.8032353320.

The spelling of 21439364 in words is "twenty-one million, four hundred thirty-nine thousand, three hundred sixty-four".