21239696 has 10 divisors (see below), whose sum is σ = 41151942. Its totient is φ = 10619840.

The previous prime is 21239693. The next prime is 21239707. The reversal of 21239696 is 69693212.

It can be written as a sum of positive squares in only one way, i.e., 20830096 + 409600 = 4564^2 + 640^2 .

It is a super-2 number, since 2×21239696² = 902249372344832, which contains 22 as substring.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663725 + ... + 663756.

Almost surely, 2^21239696 is an apocalyptic number.

It is an amenable number.

21239696 is a deficient number, since it is larger than the sum of its proper divisors (19912246).

21239696 is a wasteful number, since it uses less digits than its factorization.

21239696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327489 (or 1327483 counting only the distinct ones).

The product of its digits is 34992, while the sum is 38.

The square root of 21239696 is about 4608.6544674124. The cubic root of 21239696 is about 276.9381364713.

The spelling of 21239696 in words is "twenty-one million, two hundred thirty-nine thousand, six hundred ninety-six".