21910969 has 4 divisors (see below), whose sum is σ = 22037796. Its totient is φ = 21784144.

The previous prime is 21910957. The next prime is 21910991. The reversal of 21910969 is 96901912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11594025 + 10316944 = 3405^2 + 3212^2 .

It is a cyclic number.

It is not a de Polignac number, because 21910969 - 2⁵ = 21910937 is a prime.

It is a super-2 number, since 2×21910969² = 960181125037922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21910169) 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, 63154 + ... + 63499.

It is an arithmetic number, because the mean of its divisors is an integer number (5509449).

Almost surely, 2^21910969 is an apocalyptic number.

It is an amenable number.

21910969 is a deficient number, since it is larger than the sum of its proper divisors (126827).

21910969 is a wasteful number, since it uses less digits than its factorization.

21910969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126826.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 21910969 is about 4680.9154019273. The cubic root of 21910969 is about 279.8254396659.

The spelling of 21910969 in words is "twenty-one million, nine hundred ten thousand, nine hundred sixty-nine".