21887173 has 16 divisors (see below), whose sum is σ = 27849600. Its totient is φ = 17052000.

The previous prime is 21887167. The next prime is 21887179. The reversal of 21887173 is 37178812.

It is an interprime number because it is at equal distance from previous prime (21887167) and next prime (21887179).

It is not a de Polignac number, because 21887173 - 2¹⁷ = 21756101 is a prime.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21887179) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 873 + ... + 6673.

It is an arithmetic number, because the mean of its divisors is an integer number (1740600).

Almost surely, 2^21887173 is an apocalyptic number.

It is an amenable number.

21887173 is a deficient number, since it is larger than the sum of its proper divisors (5962427).

21887173 is an equidigital number, since it uses as much as digits as its factorization.

21887173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5833 (or 5819 counting only the distinct ones).

The product of its digits is 18816, while the sum is 37.

The square root of 21887173 is about 4678.3729009133. The cubic root of 21887173 is about 279.7241032356.

The spelling of 21887173 in words is "twenty-one million, eight hundred eighty-seven thousand, one hundred seventy-three".