21629365 has 4 divisors (see below), whose sum is σ = 25955244. Its totient is φ = 17303488.

The previous prime is 21629359. The next prime is 21629371. The reversal of 21629365 is 56392612.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21629359) and next prime (21629371).

It can be written as a sum of positive squares in 2 ways, for example, as 12229009 + 9400356 = 3497^2 + 3066^2 .

It is a cyclic number.

It is not a de Polignac number, because 21629365 - 2³ = 21629357 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 21629365.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2162932 + ... + 2162941.

It is an arithmetic number, because the mean of its divisors is an integer number (6488811).

Almost surely, 2^21629365 is an apocalyptic number.

It is an amenable number.

21629365 is a deficient number, since it is larger than the sum of its proper divisors (4325879).

21629365 is an equidigital number, since it uses as much as digits as its factorization.

21629365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4325878.

The product of its digits is 19440, while the sum is 34.

The square root of 21629365 is about 4650.7381134611. The cubic root of 21629365 is about 278.6214768097.

The spelling of 21629365 in words is "twenty-one million, six hundred twenty-nine thousand, three hundred sixty-five".