21930719 has 4 divisors (see below), whose sum is σ = 21954144. Its totient is φ = 21907296.

The previous prime is 21930709. The next prime is 21930721. The reversal of 21930719 is 91703912.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21930719 - 2⁸ = 21930463 is a prime.

It is a super-2 number, since 2×21930719² = 961912871713922, 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 (21930709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10247 + ... + 12200.

It is an arithmetic number, because the mean of its divisors is an integer number (5488536).

Almost surely, 2^21930719 is an apocalyptic number.

21930719 is a deficient number, since it is larger than the sum of its proper divisors (23425).

21930719 is an equidigital number, since it uses as much as digits as its factorization.

21930719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23424.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21930719 is about 4683.0245568436. The cubic root of 21930719 is about 279.9094903038.

The spelling of 21930719 in words is "twenty-one million, nine hundred thirty thousand, seven hundred nineteen".