21985412 has 6 divisors (see below), whose sum is σ = 38474478. Its totient is φ = 10992704.

The previous prime is 21985387. The next prime is 21985423. The reversal of 21985412 is 21458912.

It can be written as a sum of positive squares in only one way, i.e., 11383876 + 10601536 = 3374^2 + 3256^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2748173 + ... + 2748180.

It is an arithmetic number, because the mean of its divisors is an integer number (6412413).

Almost surely, 2^21985412 is an apocalyptic number.

It is an amenable number.

21985412 is a deficient number, since it is larger than the sum of its proper divisors (16489066).

21985412 is a wasteful number, since it uses less digits than its factorization.

21985412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5496357 (or 5496355 counting only the distinct ones).

The product of its digits is 5760, while the sum is 32.

The square root of 21985412 is about 4688.8604159220. The cubic root of 21985412 is about 280.1419858111.

The spelling of 21985412 in words is "twenty-one million, nine hundred eighty-five thousand, four hundred twelve".