21980084 has 12 divisors (see below), whose sum is σ = 43960224. Its totient is φ = 9420024.

The previous prime is 21980053. The next prime is 21980117. The reversal of 21980084 is 48008912.

It is a happy number.

21980084 is an admirable number.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21980084.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 392474 + ... + 392529.

It is an arithmetic number, because the mean of its divisors is an integer number (3663352).

Almost surely, 2^21980084 is an apocalyptic number.

It is an amenable number.

21980084 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21980084 is a wasteful number, since it uses less digits than its factorization.

21980084 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785014 (or 785012 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21980084 is about 4688.2922263869. The cubic root of 21980084 is about 280.1193538784.

Adding to 21980084 its reverse (48008912), we get a palindrome (69988996).

The spelling of 21980084 in words is "twenty-one million, nine hundred eighty thousand, eighty-four".