21880871 has 4 divisors (see below), whose sum is σ = 21918000. Its totient is φ = 21843744.

The previous prime is 21880849. The next prime is 21880879. The reversal of 21880871 is 17808812.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21880871 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 (21880879) 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, 17666 + ... + 18863.

It is an arithmetic number, because the mean of its divisors is an integer number (5479500).

Almost surely, 2^21880871 is an apocalyptic number.

21880871 is a deficient number, since it is larger than the sum of its proper divisors (37129).

21880871 is an equidigital number, since it uses as much as digits as its factorization.

21880871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37128.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 21880871 is about 4677.6993276610. The cubic root of 21880871 is about 279.6972535596.

The spelling of 21880871 in words is "twenty-one million, eight hundred eighty thousand, eight hundred seventy-one".