21881461 has 8 divisors (see below), whose sum is σ = 25539840. Its totient is φ = 18356208.

The previous prime is 21881459. The next prime is 21881477. The reversal of 21881461 is 16418812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21881461 - 2¹ = 21881459 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 (21881491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32926 + ... + 33583.

It is an arithmetic number, because the mean of its divisors is an integer number (3192480).

Almost surely, 2^21881461 is an apocalyptic number.

It is an amenable number.

21881461 is a deficient number, since it is larger than the sum of its proper divisors (3658379).

21881461 is an equidigital number, since it uses as much as digits as its factorization.

21881461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66563.

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

The square root of 21881461 is about 4677.7623924265. The cubic root of 21881461 is about 279.6997674737.

The spelling of 21881461 in words is "twenty-one million, eight hundred eighty-one thousand, four hundred sixty-one".