21972669 has 4 divisors (see below), whose sum is σ = 29296896. Its totient is φ = 14648444.

The previous prime is 21972667. The next prime is 21972677. The reversal of 21972669 is 96627912.

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 21972669 - 2¹ = 21972667 is a prime.

It is a super-2 number, since 2×21972669² = 965596365967122, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21972669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21972661) 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, 3662109 + ... + 3662114.

It is an arithmetic number, because the mean of its divisors is an integer number (7324224).

Almost surely, 2^21972669 is an apocalyptic number.

It is an amenable number.

21972669 is a deficient number, since it is larger than the sum of its proper divisors (7324227).

21972669 is an equidigital number, since it uses as much as digits as its factorization.

21972669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7324226.

The product of its digits is 81648, while the sum is 42.

The square root of 21972669 is about 4687.5013599998. The cubic root of 21972669 is about 280.0878508350.

The spelling of 21972669 in words is "twenty-one million, nine hundred seventy-two thousand, six hundred sixty-nine".