21608746 has 4 divisors (see below), whose sum is σ = 32413122. Its totient is φ = 10804372.

The previous prime is 21608711. The next prime is 21608749. The reversal of 21608746 is 64780612.

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., 10817521 + 10791225 = 3289^2 + 3285^2 .

It is not an unprimeable number, because it can be changed into a prime (21608749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5402185 + ... + 5402188.

Almost surely, 2^21608746 is an apocalyptic number.

21608746 is a deficient number, since it is larger than the sum of its proper divisors (10804376).

21608746 is a wasteful number, since it uses less digits than its factorization.

21608746 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10804375.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 21608746 is about 4648.5208400092. The cubic root of 21608746 is about 278.5329132187.

The spelling of 21608746 in words is "twenty-one million, six hundred eight thousand, seven hundred forty-six".