21973769 has 4 divisors (see below), whose sum is σ = 22441344. Its totient is φ = 21506196.

The previous prime is 21973753. The next prime is 21973781. The reversal of 21973769 is 96737912.

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 21973769 - 2⁴ = 21973753 is a prime.

It is a super-2 number, since 2×21973769² = 965693048130722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21973729) 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, 233717 + ... + 233810.

It is an arithmetic number, because the mean of its divisors is an integer number (5610336).

Almost surely, 2^21973769 is an apocalyptic number.

It is an amenable number.

21973769 is a deficient number, since it is larger than the sum of its proper divisors (467575).

21973769 is an equidigital number, since it uses as much as digits as its factorization.

21973769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467574.

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

The square root of 21973769 is about 4687.6186918306. The cubic root of 21973769 is about 280.0925246944.

The spelling of 21973769 in words is "twenty-one million, nine hundred seventy-three thousand, seven hundred sixty-nine".