21974869 has 4 divisors (see below), whose sum is σ = 25114144. Its totient is φ = 18835596.

The previous prime is 21974851. The next prime is 21974881. The reversal of 21974869 is 96847912.

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 21974869 - 2⁹ = 21974357 is a prime.

It is a super-2 number, since 2×21974869² = 965789735134322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974809) 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, 1569627 + ... + 1569640.

It is an arithmetic number, because the mean of its divisors is an integer number (6278536).

Almost surely, 2^21974869 is an apocalyptic number.

It is an amenable number.

21974869 is a deficient number, since it is larger than the sum of its proper divisors (3139275).

21974869 is an equidigital number, since it uses as much as digits as its factorization.

21974869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3139274.

The product of its digits is 217728, while the sum is 46.

The square root of 21974869 is about 4687.7360207247. The cubic root of 21974869 is about 280.0971983978.

The spelling of 21974869 in words is "twenty-one million, nine hundred seventy-four thousand, eight hundred sixty-nine".