21231369 has 32 divisors (see below), whose sum is σ = 33177600. Its totient is φ = 13392720.

The previous prime is 21231359. The next prime is 21231389. The reversal of 21231369 is 96313212.

It is not a de Polignac number, because 21231369 - 2⁷ = 21231241 is a prime.

It is a super-2 number, since 2×21231369² = 901542059228322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21231359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 111064 + ... + 111254.

It is an arithmetic number, because the mean of its divisors is an integer number (1036800).

Almost surely, 2^21231369 is an apocalyptic number.

It is an amenable number.

21231369 is a deficient number, since it is larger than the sum of its proper divisors (11946231).

21231369 is a wasteful number, since it uses less digits than its factorization.

21231369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 396 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21231369 is about 4607.7509698333. The cubic root of 21231369 is about 276.9019406411.

The spelling of 21231369 in words is "twenty-one million, two hundred thirty-one thousand, three hundred sixty-nine".