42623856721 has 2 divisors, whose sum is σ = 42623856722. Its totient is φ = 42623856720.

The previous prime is 42623856647. The next prime is 42623856757. The reversal of 42623856721 is 12765832624.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37690339600 + 4933517121 = 194140^2 + 70239^2 .

It is a cyclic number.

It is not a de Polignac number, because 42623856721 - 2²³ = 42615468113 is a prime.

It is not a weakly prime, because it can be changed into another prime (42323856721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21311928360 + 21311928361.

It is an arithmetic number, because the mean of its divisors is an integer number (21311928361).

Almost surely, 2^42623856721 is an apocalyptic number.

It is an amenable number.

42623856721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42623856721 is an equidigital number, since it uses as much as digits as its factorization.

42623856721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 967680, while the sum is 46.

The spelling of 42623856721 in words is "forty-two billion, six hundred twenty-three million, eight hundred fifty-six thousand, seven hundred twenty-one".