21372919 has 8 divisors (see below), whose sum is σ = 22118400. Its totient is φ = 20631000.

The previous prime is 21372889. The next prime is 21372937. The reversal of 21372919 is 91927312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21372919 - 2⁵ = 21372887 is a prime.

It is a super-2 number, since 2×21372919² = 913603333161122, 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 (21372019) 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, 17994 + ... + 19144.

It is an arithmetic number, because the mean of its divisors is an integer number (2764800).

Almost surely, 2^21372919 is an apocalyptic number.

21372919 is a deficient number, since it is larger than the sum of its proper divisors (745481).

21372919 is a wasteful number, since it uses less digits than its factorization.

21372919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781.

The product of its digits is 6804, while the sum is 34.

The square root of 21372919 is about 4623.0854415639. The cubic root of 21372919 is about 277.5159485464.

The spelling of 21372919 in words is "twenty-one million, three hundred seventy-two thousand, nine hundred nineteen".