21621368 has 8 divisors (see below), whose sum is σ = 40540080. Its totient is φ = 10810680.

The previous prime is 21621337. The next prime is 21621371. The reversal of 21621368 is 86312612.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21621368.

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 as a sum of consecutive naturals, namely, 1351328 + ... + 1351343.

It is an arithmetic number, because the mean of its divisors is an integer number (5067510).

Almost surely, 2^21621368 is an apocalyptic number.

It is an amenable number.

21621368 is a deficient number, since it is larger than the sum of its proper divisors (18918712).

21621368 is a wasteful number, since it uses less digits than its factorization.

21621368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2702677 (or 2702673 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 21621368 is about 4649.8782779767. The cubic root of 21621368 is about 278.5871344453.

The spelling of 21621368 in words is "twenty-one million, six hundred twenty-one thousand, three hundred sixty-eight".