21988492 has 6 divisors (see below), whose sum is σ = 38479868. Its totient is φ = 10994244.

The previous prime is 21988459. The next prime is 21988511. The reversal of 21988492 is 29488912.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2748558 + ... + 2748565.

Almost surely, 2^21988492 is an apocalyptic number.

It is an amenable number.

21988492 is a deficient number, since it is larger than the sum of its proper divisors (16491376).

21988492 is a wasteful number, since it uses less digits than its factorization.

21988492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5497127 (or 5497125 counting only the distinct ones).

The product of its digits is 82944, while the sum is 43.

The square root of 21988492 is about 4689.1888424332. The cubic root of 21988492 is about 280.1550671674.

The spelling of 21988492 in words is "twenty-one million, nine hundred eighty-eight thousand, four hundred ninety-two".