91721112061 has 8 divisors (see below), whose sum is σ = 97119420984. Its totient is φ = 86323130880.

The previous prime is 91721112059. The next prime is 91721112071. The reversal of 91721112061 is 16021112719.

It can be written as a sum of positive squares in 4 ways, for example, as 41003820036 + 50717292025 = 202494^2 + 225205^2 .

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 91721112061 - 2¹ = 91721112059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91721112071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 716791 + ... + 835003.

It is an arithmetic number, because the mean of its divisors is an integer number (12139927623).

Almost surely, 2^91721112061 is an apocalyptic number.

It is an amenable number.

91721112061 is a deficient number, since it is larger than the sum of its proper divisors (5398308923).

91721112061 is a wasteful number, since it uses less digits than its factorization.

91721112061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163871.

The product of its (nonzero) digits is 1512, while the sum is 31.

The spelling of 91721112061 in words is "ninety-one billion, seven hundred twenty-one million, one hundred twelve thousand, sixty-one".