21634746659 has 4 divisors (see below), whose sum is σ = 21682931400. Its totient is φ = 21586561920.

The previous prime is 21634746629. The next prime is 21634746667. The reversal of 21634746659 is 95664743612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21634746659 is a prime.

It is a super-2 number, since 2×21634746659² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21634746659.

It is not an unprimeable number, because it can be changed into a prime (21634746629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24091697 + ... + 24092594.

It is an arithmetic number, because the mean of its divisors is an integer number (5420732850).

Almost surely, 2^21634746659 is an apocalyptic number.

21634746659 is a deficient number, since it is larger than the sum of its proper divisors (48184741).

21634746659 is an equidigital number, since it uses as much as digits as its factorization.

21634746659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48184740.

The product of its digits is 6531840, while the sum is 53.

The spelling of 21634746659 in words is "twenty-one billion, six hundred thirty-four million, seven hundred forty-six thousand, six hundred fifty-nine".