21397369 has 8 divisors (see below), whose sum is σ = 24953600. Its totient is φ = 18340308.

The previous prime is 21397349. The next prime is 21397379. The reversal of 21397369 is 96379312.

It is not a de Polignac number, because 21397369 - 2¹¹ = 21395321 is a prime.

It is a super-2 number, since 2×21397369² = 915694800244322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21397349) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30849 + ... + 31534.

It is an arithmetic number, because the mean of its divisors is an integer number (3119200).

Almost surely, 2^21397369 is an apocalyptic number.

It is an amenable number.

21397369 is a deficient number, since it is larger than the sum of its proper divisors (3556231).

21397369 is an frugal number, since it uses more digits than its factorization.

21397369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62404 (or 62390 counting only the distinct ones).

The product of its digits is 61236, while the sum is 40.

The square root of 21397369 is about 4625.7290236243. The cubic root of 21397369 is about 277.6217316201.

The spelling of 21397369 in words is "twenty-one million, three hundred ninety-seven thousand, three hundred sixty-nine".