21239634 has 32 divisors (see below), whose sum is σ = 45944640. Its totient is φ = 6507072.

The previous prime is 21239623. The next prime is 21239639. The reversal of 21239634 is 43693212.

It is a super-2 number, since 2×21239634² = 902244104907912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21239639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24297 + ... + 25155.

It is an arithmetic number, because the mean of its divisors is an integer number (1435770).

Almost surely, 2^21239634 is an apocalyptic number.

21239634 is an abundant number, since it is smaller than the sum of its proper divisors (24705006).

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

21239634 is a wasteful number, since it uses less digits than its factorization.

21239634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1194.

The product of its digits is 7776, while the sum is 30.

The square root of 21239634 is about 4608.6477409323. The cubic root of 21239634 is about 276.9378670045.

The spelling of 21239634 in words is "twenty-one million, two hundred thirty-nine thousand, six hundred thirty-four".