21366385 has 16 divisors (see below), whose sum is σ = 26248320. Its totient is φ = 16692480.

The previous prime is 21366377. The next prime is 21366391. The reversal of 21366385 is 58366312.

It is not a de Polignac number, because 21366385 - 2³ = 21366377 is a prime.

Its product of digits (25920) is a multiple of the sum of its prime divisors (648).

It is a self number, because there is not a number n which added to its sum of digits gives 21366385.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49129 + ... + 49561.

It is an arithmetic number, because the mean of its divisors is an integer number (1640520).

Almost surely, 2^21366385 is an apocalyptic number.

It is an amenable number.

21366385 is a deficient number, since it is larger than the sum of its proper divisors (4881935).

21366385 is a wasteful number, since it uses less digits than its factorization.

21366385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648.

The product of its digits is 25920, while the sum is 34.

The square root of 21366385 is about 4622.3787166350. The cubic root of 21366385 is about 277.4876654962.

The spelling of 21366385 in words is "twenty-one million, three hundred sixty-six thousand, three hundred eighty-five".