21897927 has 6 divisors (see below), whose sum is σ = 31630352. Its totient is φ = 14598612.

The previous prime is 21897913. The next prime is 21897949. The reversal of 21897927 is 72979812.

It is not a de Polignac number, because 21897927 - 2¹¹ = 21895879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21897907) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1216543 + ... + 1216560.

Almost surely, 2^21897927 is an apocalyptic number.

21897927 is a deficient number, since it is larger than the sum of its proper divisors (9732425).

21897927 is a wasteful number, since it uses less digits than its factorization.

21897927 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2433109 (or 2433106 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 21897927 is about 4679.5220909832. The cubic root of 21897927 is about 279.7699087624.

The spelling of 21897927 in words is "twenty-one million, eight hundred ninety-seven thousand, nine hundred twenty-seven".