21399876 has 45 divisors (see below), whose sum is σ = 56162029. Its totient is φ = 7105536.

The previous prime is 21399839. The next prime is 21399901. The reversal of 21399876 is 67899312.

The square root of 21399876 is 4626.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 21068100 + 331776 = 4590^2 + 576^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 83140 + ... + 83396.

Almost surely, 2^21399876 is an apocalyptic number.

21399876 is the 4626-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21399876

21399876 is an abundant number, since it is smaller than the sum of its proper divisors (34762153).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21399876 is an equidigital number, since it uses as much as digits as its factorization.

21399876 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530 (or 262 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The cubic root of 21399876 is about 277.6325736151.

The spelling of 21399876 in words is "twenty-one million, three hundred ninety-nine thousand, eight hundred seventy-six".