123721856565659 has 16 divisors (see below), whose sum is σ = 139603574283264. Its totient is φ = 108665785761600.

The previous prime is 123721856565623. The next prime is 123721856565677. The reversal of 123721856565659 is 956565658127321.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123721856565659 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123721856565592 and 123721856565601.

It is not an unprimeable number, because it can be changed into a prime (123721856565679) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1331642099 + ... + 1331735004.

It is an arithmetic number, because the mean of its divisors is an integer number (8725223392704).

Almost surely, 2^{123721856565659} is an apocalyptic number.

123721856565659 is a deficient number, since it is larger than the sum of its proper divisors (15881717717605).

123721856565659 is a wasteful number, since it uses less digits than its factorization.

123721856565659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2663377258.

The product of its digits is 816480000, while the sum is 71.

The spelling of 123721856565659 in words is "one hundred twenty-three trillion, seven hundred twenty-one billion, eight hundred fifty-six million, five hundred sixty-five thousand, six hundred fifty-nine".