21757089 has 4 divisors (see below), whose sum is σ = 29009456. Its totient is φ = 14504724.

The previous prime is 21757079. The next prime is 21757091. The reversal of 21757089 is 98075712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21757089 - 2¹⁵ = 21724321 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21757049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3626179 + ... + 3626184.

It is an arithmetic number, because the mean of its divisors is an integer number (7252364).

Almost surely, 2^21757089 is an apocalyptic number.

It is an amenable number.

21757089 is a deficient number, since it is larger than the sum of its proper divisors (7252367).

21757089 is an equidigital number, since it uses as much as digits as its factorization.

21757089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7252366.

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 21757089 is about 4664.4494852019. The cubic root of 21757089 is about 279.1688319230.

The spelling of 21757089 in words is "twenty-one million, seven hundred fifty-seven thousand, eighty-nine".