21394459687 has 2 divisors, whose sum is σ = 21394459688. Its totient is φ = 21394459686.

The previous prime is 21394459621. The next prime is 21394459721. The reversal of 21394459687 is 78695449312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21394459687 - 2¹⁵ = 21394426919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21394259687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10697229843 + 10697229844.

It is an arithmetic number, because the mean of its divisors is an integer number (10697229844).

Almost surely, 2^21394459687 is an apocalyptic number.

21394459687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21394459687 is an equidigital number, since it uses as much as digits as its factorization.

21394459687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13063680, while the sum is 58.

The spelling of 21394459687 in words is "twenty-one billion, three hundred ninety-four million, four hundred fifty-nine thousand, six hundred eighty-seven".