21399319 has 2 divisors, whose sum is σ = 21399320. Its totient is φ = 21399318.

The previous prime is 21399307. The next prime is 21399353. The reversal of 21399319 is 91399312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21399319 - 2¹⁵ = 21366551 is a prime.

It is a super-2 number, since 2×21399319² = 915861707327522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21399019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10699659 + 10699660.

It is an arithmetic number, because the mean of its divisors is an integer number (10699660).

Almost surely, 2^21399319 is an apocalyptic number.

21399319 is a deficient number, since it is larger than the sum of its proper divisors (1).

21399319 is an equidigital number, since it uses as much as digits as its factorization.

21399319 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13122, while the sum is 37.

The square root of 21399319 is about 4625.9397964089. The cubic root of 21399319 is about 277.6301648366.

The spelling of 21399319 in words is "twenty-one million, three hundred ninety-nine thousand, three hundred nineteen".