21436514639 has 2 divisors, whose sum is σ = 21436514640. Its totient is φ = 21436514638.

The previous prime is 21436514581. The next prime is 21436514641. The reversal of 21436514639 is 93641563412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21436514639 is a prime.

It is a super-2 number, since 2×21436514639² (a number of 21 digits) contains 22 as substring.

Together with 21436514641, 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 21436514639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21436514689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10718257319 + 10718257320.

It is an arithmetic number, because the mean of its divisors is an integer number (10718257320).

Almost surely, 2^21436514639 is an apocalyptic number.

21436514639 is a deficient number, since it is larger than the sum of its proper divisors (1).

21436514639 is an equidigital number, since it uses as much as digits as its factorization.

21436514639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 466560, while the sum is 44.

The spelling of 21436514639 in words is "twenty-one billion, four hundred thirty-six million, five hundred fourteen thousand, six hundred thirty-nine".