21742319 has 2 divisors, whose sum is σ = 21742320. Its totient is φ = 21742318.

The previous prime is 21742313. The next prime is 21742333. The reversal of 21742319 is 91324712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21742319 is a prime.

It is a super-2 number, since 2×21742319² = 945456870995522, 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 = 21742291 and 21742300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21742313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10871159 + 10871160.

It is an arithmetic number, because the mean of its divisors is an integer number (10871160).

Almost surely, 2^21742319 is an apocalyptic number.

21742319 is a deficient number, since it is larger than the sum of its proper divisors (1).

21742319 is an equidigital number, since it uses as much as digits as its factorization.

21742319 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21742319 is about 4662.8659641898. The cubic root of 21742319 is about 279.1056455128.

The spelling of 21742319 in words is "twenty-one million, seven hundred forty-two thousand, three hundred nineteen".