21990412 has 12 divisors (see below), whose sum is σ = 38652880. Its totient is φ = 10946736.

The previous prime is 21990373. The next prime is 21990413. The reversal of 21990412 is 21409912.

It is a happy number.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21990413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11088 + ... + 12919.

Almost surely, 2^21990412 is an apocalyptic number.

It is an amenable number.

21990412 is a deficient number, since it is larger than the sum of its proper divisors (16662468).

21990412 is a wasteful number, since it uses less digits than its factorization.

21990412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24240 (or 24238 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 21990412 is about 4689.3935642042. The cubic root of 21990412 is about 280.1632211611.

The spelling of 21990412 in words is "twenty-one million, nine hundred ninety thousand, four hundred twelve".