231721647123 has 4 divisors (see below), whose sum is σ = 308962196168. Its totient is φ = 154481098080.

The previous prime is 231721647119. The next prime is 231721647137. The reversal of 231721647123 is 321746127132.

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

It is not a de Polignac number, because 231721647123 - 2² = 231721647119 is a prime.

It is a super-2 number, since 2×231721647123² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231721647323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38620274518 + ... + 38620274523.

It is an arithmetic number, because the mean of its divisors is an integer number (77240549042).

Almost surely, 2^231721647123 is an apocalyptic number.

231721647123 is a deficient number, since it is larger than the sum of its proper divisors (77240549045).

231721647123 is an equidigital number, since it uses as much as digits as its factorization.

231721647123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77240549044.

The product of its digits is 84672, while the sum is 39.

The spelling of 231721647123 in words is "two hundred thirty-one billion, seven hundred twenty-one million, six hundred forty-seven thousand, one hundred twenty-three".