21985366 has 16 divisors (see below), whose sum is σ = 35625744. Its totient is φ = 10115424.

The previous prime is 21985361. The next prime is 21985373. The reversal of 21985366 is 66358912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21985361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8565 + ... + 10831.

It is an arithmetic number, because the mean of its divisors is an integer number (2226609).

Almost surely, 2^21985366 is an apocalyptic number.

21985366 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21985366 is a deficient number, since it is larger than the sum of its proper divisors (13640378).

21985366 is a wasteful number, since it uses less digits than its factorization.

21985366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2655.

The product of its digits is 77760, while the sum is 40.

The square root of 21985366 is about 4688.8555106764. The cubic root of 21985366 is about 280.1417904309.

The spelling of 21985366 in words is "twenty-one million, nine hundred eighty-five thousand, three hundred sixty-six".