21102671 has 4 divisors (see below), whose sum is σ = 21551712. Its totient is φ = 20653632.

The previous prime is 21102643. The next prime is 21102677. The reversal of 21102671 is 17620112.

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 21102671 - 2⁶ = 21102607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102677) 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, 224450 + ... + 224543.

It is an arithmetic number, because the mean of its divisors is an integer number (5387928).

Almost surely, 2^21102671 is an apocalyptic number.

21102671 is a deficient number, since it is larger than the sum of its proper divisors (449041).

21102671 is an equidigital number, since it uses as much as digits as its factorization.

21102671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449040.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21102671 is about 4593.7643605218. The cubic root of 21102671 is about 276.3413083097.

Adding to 21102671 its reverse (17620112), we get a palindrome (38722783).

The spelling of 21102671 in words is "twenty-one million, one hundred two thousand, six hundred seventy-one".