21387703679 has 2 divisors, whose sum is σ = 21387703680. Its totient is φ = 21387703678.

The previous prime is 21387703661. The next prime is 21387703681. The reversal of 21387703679 is 97630778312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21387703679 - 2¹⁶ = 21387638143 is a prime.

Together with 21387703681, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21387703679.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21387705679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10693851839 + 10693851840.

It is an arithmetic number, because the mean of its divisors is an integer number (10693851840).

Almost surely, 2^21387703679 is an apocalyptic number.

21387703679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21387703679 is an equidigital number, since it uses as much as digits as its factorization.

21387703679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2667168, while the sum is 53.

The spelling of 21387703679 in words is "twenty-one billion, three hundred eighty-seven million, seven hundred three thousand, six hundred seventy-nine".