21880381 has 4 divisors (see below), whose sum is σ = 23032000. Its totient is φ = 20728764.

The previous prime is 21880379. The next prime is 21880403. The reversal of 21880381 is 18308812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21880381 - 2¹ = 21880379 is a prime.

It is a super-2 number, since 2×21880381² = 957502145410322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880321) 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, 575781 + ... + 575818.

It is an arithmetic number, because the mean of its divisors is an integer number (5758000).

Almost surely, 2^21880381 is an apocalyptic number.

It is an amenable number.

21880381 is a deficient number, since it is larger than the sum of its proper divisors (1151619).

21880381 is a wasteful number, since it uses less digits than its factorization.

21880381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1151618.

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 21880381 is about 4677.6469511924. The cubic root of 21880381 is about 279.6951656982.

The spelling of 21880381 in words is "twenty-one million, eight hundred eighty thousand, three hundred eighty-one".