21989577 has 8 divisors (see below), whose sum is σ = 29506816. Its totient is φ = 14566032.

The previous prime is 21989557. The next prime is 21989579. The reversal of 21989577 is 77598912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21989577 - 2¹¹ = 21987529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21989579) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22873 + ... + 23814.

It is an arithmetic number, because the mean of its divisors is an integer number (3688352).

Almost surely, 2^21989577 is an apocalyptic number.

It is an amenable number.

21989577 is a deficient number, since it is larger than the sum of its proper divisors (7517239).

21989577 is a wasteful number, since it uses less digits than its factorization.

21989577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46847.

The product of its digits is 317520, while the sum is 48.

The square root of 21989577 is about 4689.3045326573. The cubic root of 21989577 is about 280.1596750815.

The spelling of 21989577 in words is "twenty-one million, nine hundred eighty-nine thousand, five hundred seventy-seven".