21743415391 has 2 divisors, whose sum is σ = 21743415392. Its totient is φ = 21743415390.

The previous prime is 21743415349. The next prime is 21743415431. The reversal of 21743415391 is 19351434712.

It is an a-pointer prime, because the next prime (21743415431) can be obtained adding 21743415391 to its sum of digits (40).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21743415391 - 2¹⁷ = 21743284319 is a prime.

It is a super-2 number, since 2×21743415391² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21743415691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10871707695 + 10871707696.

It is an arithmetic number, because the mean of its divisors is an integer number (10871707696).

Almost surely, 2^21743415391 is an apocalyptic number.

21743415391 is a deficient number, since it is larger than the sum of its proper divisors (1).

21743415391 is an equidigital number, since it uses as much as digits as its factorization.

21743415391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 40.

The spelling of 21743415391 in words is "twenty-one billion, seven hundred forty-three million, four hundred fifteen thousand, three hundred ninety-one".