21985269 has 4 divisors (see below), whose sum is σ = 29313696. Its totient is φ = 14656844.

The previous prime is 21985259. The next prime is 21985273. The reversal of 21985269 is 96258912.

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 21985269 - 2⁴ = 21985253 is a prime.

It is a super-2 number, since 2×21985269² = 966704106004722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21985269.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21985259) 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, 3664209 + ... + 3664214.

It is an arithmetic number, because the mean of its divisors is an integer number (7328424).

Almost surely, 2^21985269 is an apocalyptic number.

It is an amenable number.

21985269 is a deficient number, since it is larger than the sum of its proper divisors (7328427).

21985269 is an equidigital number, since it uses as much as digits as its factorization.

21985269 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7328426.

The product of its digits is 77760, while the sum is 42.

The square root of 21985269 is about 4688.8451669894. The cubic root of 21985269 is about 280.1413784327.

The spelling of 21985269 in words is "twenty-one million, nine hundred eighty-five thousand, two hundred sixty-nine".