21179365 has 12 divisors (see below), whose sum is σ = 27000036. Its totient is φ = 15945728.

The previous prime is 21179363. The next prime is 21179369. The reversal of 21179365 is 56397112.

It can be written as a sum of positive squares in 6 ways, for example, as 6441444 + 14737921 = 2538^2 + 3839^2 .

It is not a de Polignac number, because 21179365 - 2¹ = 21179363 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21179365.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21179363) 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 11 ways as a sum of consecutive naturals, for example, 5884 + ... + 8773.

It is an arithmetic number, because the mean of its divisors is an integer number (2250003).

Almost surely, 2^21179365 is an apocalyptic number.

It is an amenable number.

21179365 is a deficient number, since it is larger than the sum of its proper divisors (5820671).

21179365 is a wasteful number, since it uses less digits than its factorization.

21179365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14696 (or 14679 counting only the distinct ones).

The product of its digits is 11340, while the sum is 34.

The square root of 21179365 is about 4602.1044099412. The cubic root of 21179365 is about 276.6756750990.

The spelling of 21179365 in words is "twenty-one million, one hundred seventy-nine thousand, three hundred sixty-five".