21364634 has 4 divisors (see below), whose sum is σ = 32046954. Its totient is φ = 10682316.

The previous prime is 21364633. The next prime is 21364639. The reversal of 21364634 is 43646312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 7038409 = 3785^2 + 2653^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21364597 and 21364606.

It is not an unprimeable number, because it can be changed into a prime (21364633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5341157 + ... + 5341160.

Almost surely, 2^21364634 is an apocalyptic number.

21364634 is a deficient number, since it is larger than the sum of its proper divisors (10682320).

21364634 is a wasteful number, since it uses less digits than its factorization.

21364634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10682319.

The product of its digits is 10368, while the sum is 29.

The square root of 21364634 is about 4622.1893081093. The cubic root of 21364634 is about 277.4800851439.

The spelling of 21364634 in words is "twenty-one million, three hundred sixty-four thousand, six hundred thirty-four".