21365880439 has 2 divisors, whose sum is σ = 21365880440. Its totient is φ = 21365880438.

The previous prime is 21365880421. The next prime is 21365880443. The reversal of 21365880439 is 93408856312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21365880439 - 2⁷ = 21365880311 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21365880392 and 21365880401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21365880469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682940219 + 10682940220.

It is an arithmetic number, because the mean of its divisors is an integer number (10682940220).

Almost surely, 2^21365880439 is an apocalyptic number.

21365880439 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365880439 is an equidigital number, since it uses as much as digits as its factorization.

21365880439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1244160, while the sum is 49.

The spelling of 21365880439 in words is "twenty-one billion, three hundred sixty-five million, eight hundred eighty thousand, four hundred thirty-nine".