21268919 has 8 divisors (see below), whose sum is σ = 25145760. Its totient is φ = 17601696.

The previous prime is 21268909. The next prime is 21268927. The reversal of 21268919 is 91986212.

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

It is not a de Polignac number, because 21268919 - 2⁴ = 21268903 is a prime.

It is a super-2 number, since 2×21268919² = 904733830857122, 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 (21268909) 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, 52184 + ... + 52589.

It is an arithmetic number, because the mean of its divisors is an integer number (3143220).

Almost surely, 2^21268919 is an apocalyptic number.

21268919 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21268919 is a deficient number, since it is larger than the sum of its proper divisors (3876841).

21268919 is a wasteful number, since it uses less digits than its factorization.

21268919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104809.

The product of its digits is 15552, while the sum is 38.

The square root of 21268919 is about 4611.8238257765. The cubic root of 21268919 is about 277.0650882943.

The spelling of 21268919 in words is "twenty-one million, two hundred sixty-eight thousand, nine hundred nineteen".