21886921 has 8 divisors (see below), whose sum is σ = 25049024. Its totient is φ = 18733680.

The previous prime is 21886919. The next prime is 21886927. The reversal of 21886921 is 12968812.

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

It is not a de Polignac number, because 21886921 - 2¹ = 21886919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21886927) 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, 4411 + ... + 7951.

It is an arithmetic number, because the mean of its divisors is an integer number (3131128).

Almost surely, 2^21886921 is an apocalyptic number.

It is an amenable number.

21886921 is a deficient number, since it is larger than the sum of its proper divisors (3162103).

21886921 is an equidigital number, since it uses as much as digits as its factorization.

21886921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4431.

The product of its digits is 13824, while the sum is 37.

The square root of 21886921 is about 4678.3459683952. The cubic root of 21886921 is about 279.7230296884.

The spelling of 21886921 in words is "twenty-one million, eight hundred eighty-six thousand, nine hundred twenty-one".