21369897 has 24 divisors (see below), whose sum is σ = 32727240. Its totient is φ = 13413120.

The previous prime is 21369893. The next prime is 21369911. The reversal of 21369897 is 79896312.

It can be written as a sum of positive squares in 4 ways, for example, as 767376 + 20602521 = 876^2 + 4539^2 .

It is not a de Polignac number, because 21369897 - 2² = 21369893 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21369893) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9703 + ... + 11699.

It is an arithmetic number, because the mean of its divisors is an integer number (1363635).

Almost surely, 2^21369897 is an apocalyptic number.

It is an amenable number.

21369897 is a deficient number, since it is larger than the sum of its proper divisors (11357343).

21369897 is a wasteful number, since it uses less digits than its factorization.

21369897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2073 (or 2070 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 21369897 is about 4622.7585920098. The cubic root of 21369897 is about 277.5028682440.

The spelling of 21369897 in words is "twenty-one million, three hundred sixty-nine thousand, eight hundred ninety-seven".