231721914891 has 8 divisors (see below), whose sum is σ = 308965110480. Its totient is φ = 154479997952.

The previous prime is 231721914847. The next prime is 231721914901. The reversal of 231721914891 is 198419127132.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 231721914891 - 2¹³ = 231721906699 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 231721914891.

It is not an unprimeable number, because it can be changed into a prime (231721914821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246391 + ... + 723983.

It is an arithmetic number, because the mean of its divisors is an integer number (38620638810).

Almost surely, 2^231721914891 is an apocalyptic number.

231721914891 is a deficient number, since it is larger than the sum of its proper divisors (77243195589).

231721914891 is a wasteful number, since it uses less digits than its factorization.

231721914891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639325.

The product of its digits is 217728, while the sum is 48.

The spelling of 231721914891 in words is "two hundred thirty-one billion, seven hundred twenty-one million, nine hundred fourteen thousand, eight hundred ninety-one".