127791197721 has 48 divisors (see below), whose sum is σ = 213171591360. Its totient is φ = 75560126400.

The previous prime is 127791197693. The next prime is 127791197749.

127791197721 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (127791197693) and next prime (127791197749).

It is not a de Polignac number, because 127791197721 - 2⁷ = 127791197593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (127791197761) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 343075 + ... + 610968.

It is an arithmetic number, because the mean of its divisors is an integer number (4441074820).

Almost surely, 2^127791197721 is an apocalyptic number.

127791197721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

127791197721 is a deficient number, since it is larger than the sum of its proper divisors (85380393639).

127791197721 is a wasteful number, since it uses less digits than its factorization.

127791197721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954115 (or 954098 counting only the distinct ones).

The product of its digits is 777924, while the sum is 54.

The spelling of 127791197721 in words is "one hundred twenty-seven billion, seven hundred ninety-one million, one hundred ninety-seven thousand, seven hundred twenty-one".