21013169 has 4 divisors (see below), whose sum is σ = 21047844. Its totient is φ = 20978496.

The previous prime is 21013159. The next prime is 21013177. The reversal of 21013169 is 96131012.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8196769 + 12816400 = 2863^2 + 3580^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013169 - 2⁸ = 21012913 is a prime.

It is a super-2 number, since 2×21013169² = 883106542845122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21013159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16412 + ... + 17645.

It is an arithmetic number, because the mean of its divisors is an integer number (5261961).

Almost surely, 2^21013169 is an apocalyptic number.

It is an amenable number.

21013169 is a deficient number, since it is larger than the sum of its proper divisors (34675).

21013169 is an equidigital number, since it uses as much as digits as its factorization.

21013169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34674.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21013169 is about 4584.0123254634. The cubic root of 21013169 is about 275.9500758612.

The spelling of 21013169 in words is "twenty-one million, thirteen thousand, one hundred sixty-nine".