21723419 has 2 divisors, whose sum is σ = 21723420. Its totient is φ = 21723418.

The previous prime is 21723409. The next prime is 21723451. The reversal of 21723419 is 91432712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21723419 - 2²⁴ = 4946203 is a prime.

It is a super-2 number, since 2×21723419² = 943813866099122, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21723391 and 21723400.

It is not a weakly prime, because it can be changed into another prime (21723409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861709 + 10861710.

It is an arithmetic number, because the mean of its divisors is an integer number (10861710).

Almost surely, 2^21723419 is an apocalyptic number.

21723419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723419 is an equidigital number, since it uses as much as digits as its factorization.

21723419 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 21723419 is about 4660.8388729927. The cubic root of 21723419 is about 279.0247491138.

The spelling of 21723419 in words is "twenty-one million, seven hundred twenty-three thousand, four hundred nineteen".