21388476 has 12 divisors (see below), whose sum is σ = 49906472. Its totient is φ = 7129488.

The previous prime is 21388469. The next prime is 21388517. The reversal of 21388476 is 67488312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 891175 + ... + 891198.

Almost surely, 2^21388476 is an apocalyptic number.

It is an amenable number.

21388476 is an abundant number, since it is smaller than the sum of its proper divisors (28517996).

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

21388476 is a wasteful number, since it uses less digits than its factorization.

21388476 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1782380 (or 1782378 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The square root of 21388476 is about 4624.7676698403. The cubic root of 21388476 is about 277.5832653306.

The spelling of 21388476 in words is "twenty-one million, three hundred eighty-eight thousand, four hundred seventy-six".