21773969 has 4 divisors (see below), whose sum is σ = 24884544. Its totient is φ = 18663396.

The previous prime is 21773963. The next prime is 21773977. The reversal of 21773969 is 96937712.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 21773969 - 2¹⁶ = 21708433 is a prime.

It is a super-2 number, since 2×21773969² = 948211452025922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21773963) 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, 1555277 + ... + 1555290.

It is an arithmetic number, because the mean of its divisors is an integer number (6221136).

Almost surely, 2^21773969 is an apocalyptic number.

It is an amenable number.

21773969 is a deficient number, since it is larger than the sum of its proper divisors (3110575).

21773969 is an equidigital number, since it uses as much as digits as its factorization.

21773969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3110574.

The product of its digits is 142884, while the sum is 44.

The square root of 21773969 is about 4666.2585654891. The cubic root of 21773969 is about 279.2410099570.

The spelling of 21773969 in words is "twenty-one million, seven hundred seventy-three thousand, nine hundred sixty-nine".