21896021 has 8 divisors (see below), whose sum is σ = 25448640. Its totient is φ = 18449568.

The previous prime is 21895969. The next prime is 21896027. The reversal of 21896021 is 12069812.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21896021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21896027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26096 + ... + 26921.

It is an arithmetic number, because the mean of its divisors is an integer number (3181080).

Almost surely, 2^21896021 is an apocalyptic number.

It is an amenable number.

21896021 is a deficient number, since it is larger than the sum of its proper divisors (3552619).

21896021 is an equidigital number, since it uses as much as digits as its factorization.

21896021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53083.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21896021 is about 4679.3184332764. The cubic root of 21896021 is about 279.7617914504.

The spelling of 21896021 in words is "twenty-one million, eight hundred ninety-six thousand, twenty-one".