21680271 has 16 divisors (see below), whose sum is σ = 32248320. Its totient is φ = 14395320.

The previous prime is 21680257. The next prime is 21680279. The reversal of 21680271 is 17208612.

It is not a de Polignac number, because 21680271 - 2⁷ = 21680143 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680279) 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, 5836 + ... + 8798.

It is an arithmetic number, because the mean of its divisors is an integer number (2015520).

Almost surely, 2^21680271 is an apocalyptic number.

21680271 is a deficient number, since it is larger than the sum of its proper divisors (10568049).

21680271 is a wasteful number, since it uses less digits than its factorization.

21680271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3243 (or 3237 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 21680271 is about 4656.2077917550. The cubic root of 21680271 is about 278.8398896354.

Adding to 21680271 its reverse (17208612), we get a palindrome (38888883).

The spelling of 21680271 in words is "twenty-one million, six hundred eighty thousand, two hundred seventy-one".