21992985 has 96 divisors (see below), whose sum is σ = 48625920. Its totient is φ = 9206784.

The previous prime is 21992947. The next prime is 21992989. The reversal of 21992985 is 58929912.

It is not a de Polignac number, because 21992985 - 2¹⁰ = 21991961 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21992985.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992989) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 594387 + ... + 594423.

It is an arithmetic number, because the mean of its divisors is an integer number (506520).

Almost surely, 2^21992985 is an apocalyptic number.

It is an amenable number.

21992985 is an abundant number, since it is smaller than the sum of its proper divisors (26632935).

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

21992985 is a wasteful number, since it uses less digits than its factorization.

21992985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 69 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The square root of 21992985 is about 4689.6678986896. The cubic root of 21992985 is about 280.1741476178.

It can be divided in two parts, 2199 and 2985, that added together give a square (5184 = 72²).

The spelling of 21992985 in words is "twenty-one million, nine hundred ninety-two thousand, nine hundred eighty-five".