21366169 has 4 divisors (see below), whose sum is σ = 23308560. Its totient is φ = 19423780.

The previous prime is 21366139. The next prime is 21366173. The reversal of 21366169 is 96166312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21366169 - 2⁷ = 21366041 is a prime.

It is a super-2 number, since 2×21366169² = 913026355473122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21366139) 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, 971179 + ... + 971200.

It is an arithmetic number, because the mean of its divisors is an integer number (5827140).

Almost surely, 2^21366169 is an apocalyptic number.

It is an amenable number.

21366169 is a deficient number, since it is larger than the sum of its proper divisors (1942391).

21366169 is a wasteful number, since it uses less digits than its factorization.

21366169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942390.

The product of its digits is 11664, while the sum is 34.

The square root of 21366169 is about 4622.3553519824. The cubic root of 21366169 is about 277.4867304209.

The spelling of 21366169 in words is "twenty-one million, three hundred sixty-six thousand, one hundred sixty-nine".