21349171 has 4 divisors (see below), whose sum is σ = 21393144. Its totient is φ = 21305200.

The previous prime is 21349117. The next prime is 21349183. The reversal of 21349171 is 17194312.

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

It is a cyclic number.

It is not a de Polignac number, because 21349171 - 2⁷ = 21349043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21349571) 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, 21250 + ... + 22231.

It is an arithmetic number, because the mean of its divisors is an integer number (5348286).

Almost surely, 2^21349171 is an apocalyptic number.

21349171 is a deficient number, since it is larger than the sum of its proper divisors (43973).

21349171 is an equidigital number, since it uses as much as digits as its factorization.

21349171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43972.

The product of its digits is 1512, while the sum is 28.

The square root of 21349171 is about 4620.5163131408. The cubic root of 21349171 is about 277.4131254178.

The spelling of 21349171 in words is "twenty-one million, three hundred forty-nine thousand, one hundred seventy-one".