21080919 has 4 divisors (see below), whose sum is σ = 28107896. Its totient is φ = 14053944.

The previous prime is 21080897. The next prime is 21080933. The reversal of 21080919 is 91908012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21080919 - 2⁵ = 21080887 is a prime.

It is a super-2 number, since 2×21080919² = 888810291769122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21080219) 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, 3513484 + ... + 3513489.

It is an arithmetic number, because the mean of its divisors is an integer number (7026974).

Almost surely, 2^21080919 is an apocalyptic number.

21080919 is a deficient number, since it is larger than the sum of its proper divisors (7026977).

21080919 is an equidigital number, since it uses as much as digits as its factorization.

21080919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7026976.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 21080919 is about 4591.3961928808. The cubic root of 21080919 is about 276.2463275584.

The spelling of 21080919 in words is "twenty-one million, eighty thousand, nine hundred nineteen".