21988570 has 16 divisors (see below), whose sum is σ = 39944520. Its totient is φ = 8714304.

The previous prime is 21988559. The next prime is 21988573. The reversal of 21988570 is 7588912.

It can be written as a sum of positive squares in 4 ways, for example, as 21986721 + 1849 = 4689^2 + 43^2 .

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 7 ways as a sum of consecutive naturals, for example, 8997 + ... + 11176.

Almost surely, 2^21988570 is an apocalyptic number.

21988570 is a deficient number, since it is larger than the sum of its proper divisors (17955950).

21988570 is a wasteful number, since it uses less digits than its factorization.

21988570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20289.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 21988570 is about 4689.1971594293. The cubic root of 21988570 is about 280.1553984327.

The spelling of 21988570 in words is "twenty-one million, nine hundred eighty-eight thousand, five hundred seventy".