21887169 has 4 divisors (see below), whose sum is σ = 29182896. Its totient is φ = 14591444.

The previous prime is 21887167. The next prime is 21887179. The reversal of 21887169 is 96178812.

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 21887169 - 2¹ = 21887167 is a prime.

It is a super-2 number, since 2×21887169² = 958096333669122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21887169.

It is not an unprimeable number, because it can be changed into a prime (21887167) 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 3 ways as a sum of consecutive naturals, for example, 3647859 + ... + 3647864.

It is an arithmetic number, because the mean of its divisors is an integer number (7295724).

Almost surely, 2^21887169 is an apocalyptic number.

It is an amenable number.

21887169 is a deficient number, since it is larger than the sum of its proper divisors (7295727).

21887169 is an equidigital number, since it uses as much as digits as its factorization.

21887169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7295726.

The product of its digits is 48384, while the sum is 42.

The square root of 21887169 is about 4678.3724734142. The cubic root of 21887169 is about 279.7240861953.

The spelling of 21887169 in words is "twenty-one million, eight hundred eighty-seven thousand, one hundred sixty-nine".