191456721431 has 4 divisors (see below), whose sum is σ = 201533391000. Its totient is φ = 181380051864.

The previous prime is 191456721427. The next prime is 191456721439. The reversal of 191456721431 is 134127654191.

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

It is a cyclic number.

It is not a de Polignac number, because 191456721431 - 2² = 191456721427 is a prime.

It is a super-2 number, since 2×191456721431² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191456721439) 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, 5038334756 + ... + 5038334793.

It is an arithmetic number, because the mean of its divisors is an integer number (50383347750).

Almost surely, 2^191456721431 is an apocalyptic number.

191456721431 is a deficient number, since it is larger than the sum of its proper divisors (10076669569).

191456721431 is a wasteful number, since it uses less digits than its factorization.

191456721431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10076669568.

The product of its digits is 181440, while the sum is 44.

The spelling of 191456721431 in words is "one hundred ninety-one billion, four hundred fifty-six million, seven hundred twenty-one thousand, four hundred thirty-one".