21988473 has 16 divisors (see below), whose sum is σ = 31765440. Its totient is φ = 13449024.

The previous prime is 21988459. The next prime is 21988511. The reversal of 21988473 is 37488912.

It is not a de Polignac number, because 21988473 - 2¹³ = 21980281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21988573) 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 15 ways as a sum of consecutive naturals, for example, 5118 + ... + 8376.

It is an arithmetic number, because the mean of its divisors is an integer number (1985340).

Almost surely, 2^21988473 is an apocalyptic number.

It is an amenable number.

21988473 is a deficient number, since it is larger than the sum of its proper divisors (9776967).

21988473 is a wasteful number, since it uses less digits than its factorization.

21988473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3448.

The product of its digits is 96768, while the sum is 42.

The square root of 21988473 is about 4689.1868164960. The cubic root of 21988473 is about 280.1549864745.

The spelling of 21988473 in words is "twenty-one million, nine hundred eighty-eight thousand, four hundred seventy-three".