18991979072641 has 8 divisors (see below), whose sum is σ = 19530640301480. Its totient is φ = 18454652817408.

The previous prime is 18991979072609. The next prime is 18991979072657. The reversal of 18991979072641 is 14627097919981.

It can be written as a sum of positive squares in 4 ways, for example, as 1133790521616 + 17858188551025 = 1064796^2 + 4225895^2 .

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 18991979072641 - 2⁵ = 18991979072609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18991979072681) 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, 333714546 + ... + 333771451.

It is an arithmetic number, because the mean of its divisors is an integer number (2441330037685).

Almost surely, 2^{18991979072641} is an apocalyptic number.

It is an amenable number.

18991979072641 is a deficient number, since it is larger than the sum of its proper divisors (538661228839).

18991979072641 is an equidigital number, since it uses as much as digits as its factorization.

18991979072641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667486803.

The product of its (nonzero) digits is 123451776, while the sum is 73.

The spelling of 18991979072641 in words is "eighteen trillion, nine hundred ninety-one billion, nine hundred seventy-nine million, seventy-two thousand, six hundred forty-one".