1721167478891 has 8 divisors (see below), whose sum is σ = 1990747928064. Its totient is φ = 1457511874920.

The previous prime is 1721167478857. The next prime is 1721167478897. The reversal of 1721167478891 is 1988747611271.

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 1721167478891 - 2⁶ = 1721167478827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1721167478897) 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, 1481210675 + ... + 1481211836.

It is an arithmetic number, because the mean of its divisors is an integer number (248843491008).

Almost surely, 2^{1721167478891} is an apocalyptic number.

1721167478891 is a deficient number, since it is larger than the sum of its proper divisors (269580449173).

1721167478891 is an equidigital number, since it uses as much as digits as its factorization.

1721167478891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2962422601.

The product of its digits is 9483264, while the sum is 62.

The spelling of 1721167478891 in words is "one trillion, seven hundred twenty-one billion, one hundred sixty-seven million, four hundred seventy-eight thousand, eight hundred ninety-one".