123721856565623 has 2 divisors, whose sum is σ = 123721856565624. Its totient is φ = 123721856565622.

The previous prime is 123721856565589. The next prime is 123721856565677. The reversal of 123721856565623 is 326565658127321.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123721856565623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123721856565683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61860928282811 + 61860928282812.

It is an arithmetic number, because the mean of its divisors is an integer number (61860928282812).

Almost surely, 2^{123721856565623} is an apocalyptic number.

123721856565623 is a deficient number, since it is larger than the sum of its proper divisors (1).

123721856565623 is an equidigital number, since it uses as much as digits as its factorization.

123721856565623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864000, while the sum is 62.

The spelling of 123721856565623 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 twenty-three".