21239694 has 48 divisors (see below), whose sum is σ = 53146080. Its totient is φ = 6004800.

The previous prime is 21239693. The next prime is 21239707. The reversal of 21239694 is 49693212.

It is a super-2 number, since 2×21239694² = 902249202427272, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21239693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11892 + ... + 13560.

It is an arithmetic number, because the mean of its divisors is an integer number (1107210).

Almost surely, 2^21239694 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21239694, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26573040).

21239694 is an abundant number, since it is smaller than the sum of its proper divisors (31906386).

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

21239694 is a wasteful number, since it uses less digits than its factorization.

21239694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1785 (or 1782 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 21239694 is about 4608.6542504293. The cubic root of 21239694 is about 276.9381277788.

The spelling of 21239694 in words is "twenty-one million, two hundred thirty-nine thousand, six hundred ninety-four".