128172723997 has 2 divisors, whose sum is σ = 128172723998. Its totient is φ = 128172723996.

The previous prime is 128172723937. The next prime is 128172724039. The reversal of 128172723997 is 799327271821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68798142436 + 59374581561 = 262294^2 + 243669^2 .

It is a cyclic number.

It is not a de Polignac number, because 128172723997 - 2¹⁹ = 128172199709 is a prime.

It is a super-2 number, since 2×128172723997² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128172723937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64086361998 + 64086361999.

It is an arithmetic number, because the mean of its divisors is an integer number (64086361999).

Almost surely, 2^128172723997 is an apocalyptic number.

It is an amenable number.

128172723997 is a deficient number, since it is larger than the sum of its proper divisors (1).

128172723997 is an equidigital number, since it uses as much as digits as its factorization.

128172723997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5334336, while the sum is 58.

The spelling of 128172723997 in words is "one hundred twenty-eight billion, one hundred seventy-two million, seven hundred twenty-three thousand, nine hundred ninety-seven".