21790569 has 4 divisors (see below), whose sum is σ = 29054096. Its totient is φ = 14527044.

The previous prime is 21790567. The next prime is 21790597. The reversal of 21790569 is 96509712.

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 21790569 - 2¹ = 21790567 is a prime.

It is a super-2 number, since 2×21790569² = 949657794687522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21790567) 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, 3631759 + ... + 3631764.

It is an arithmetic number, because the mean of its divisors is an integer number (7263524).

Almost surely, 2^21790569 is an apocalyptic number.

It is an amenable number.

21790569 is a deficient number, since it is larger than the sum of its proper divisors (7263527).

21790569 is an equidigital number, since it uses as much as digits as its factorization.

21790569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7263526.

The product of its (nonzero) digits is 34020, while the sum is 39.

The square root of 21790569 is about 4668.0369535812. The cubic root of 21790569 is about 279.3119543538.

The spelling of 21790569 in words is "twenty-one million, seven hundred ninety thousand, five hundred sixty-nine".