21388496 has 10 divisors (see below), whose sum is σ = 41440242. Its totient is φ = 10694240.

The previous prime is 21388469. The next prime is 21388517. The reversal of 21388496 is 69488312.

It can be written as a sum of positive squares in only one way, i.e., 14440000 + 6948496 = 3800^2 + 2636^2 .

It is a super-2 number, since 2×21388496² = 914935522284032, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 668375 + ... + 668406.

Almost surely, 2^21388496 is an apocalyptic number.

It is an amenable number.

21388496 is a deficient number, since it is larger than the sum of its proper divisors (20051746).

21388496 is a wasteful number, since it uses less digits than its factorization.

21388496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336789 (or 1336783 counting only the distinct ones).

The product of its digits is 82944, while the sum is 41.

The square root of 21388496 is about 4624.7698321106. The cubic root of 21388496 is about 277.5833518517.

The spelling of 21388496 in words is "twenty-one million, three hundred eighty-eight thousand, four hundred ninety-six".