21177171 has 12 divisors (see below), whose sum is σ = 30671472. Its totient is φ = 14080176.

The previous prime is 21177139. The next prime is 21177239. The reversal of 21177171 is 17177112.

It is not a de Polignac number, because 21177171 - 2⁵ = 21177139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21177131) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 610 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (2555956).

Almost surely, 2^21177171 is an apocalyptic number.

21177171 is a deficient number, since it is larger than the sum of its proper divisors (9494301).

21177171 is a wasteful number, since it uses less digits than its factorization.

21177171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6330 (or 6327 counting only the distinct ones).

The product of its digits is 686, while the sum is 27.

The square root of 21177171 is about 4601.8660345560. The cubic root of 21177171 is about 276.6661210292. Note that the first 3 decimals are identical.

The spelling of 21177171 in words is "twenty-one million, one hundred seventy-seven thousand, one hundred seventy-one".