21376249 has 4 divisors (see below), whose sum is σ = 21387940. Its totient is φ = 21364560.

The previous prime is 21376217. The next prime is 21376253. The reversal of 21376249 is 94267312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3356224 + 18020025 = 1832^2 + 4245^2 .

It is a cyclic number.

It is not a de Polignac number, because 21376249 - 2⁵ = 21376217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21376279) 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 3 ways as a sum of consecutive naturals, for example, 2442 + ... + 6979.

It is an arithmetic number, because the mean of its divisors is an integer number (5346985).

Almost surely, 2^21376249 is an apocalyptic number.

It is an amenable number.

21376249 is a deficient number, since it is larger than the sum of its proper divisors (11691).

21376249 is an equidigital number, since it uses as much as digits as its factorization.

21376249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11690.

The product of its digits is 18144, while the sum is 34.

The square root of 21376249 is about 4623.4455766236. The cubic root of 21376249 is about 277.5303605556.

The spelling of 21376249 in words is "twenty-one million, three hundred seventy-six thousand, two hundred forty-nine".