8991727901641 has 9 divisors (see below), whose sum is σ = 9116811520821. Its totient is φ = 8868337646112.

The previous prime is 8991727901617. The next prime is 8991727901647. The reversal of 8991727901641 is 1461097271998.

It is a happy number.

The square root of 8991727901641 is 2998621.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 2833091546041 + 6158636355600 = 1683179^2 + 2481660^2 .

It is not a de Polignac number, because 8991727901641 - 2⁹ = 8991727901129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8991727901647) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 218878795 + ... + 218919871.

It is an arithmetic number, because the mean of its divisors is an integer number (1012979057869).

Almost surely, 2^{8991727901641} is an apocalyptic number.

8991727901641 is the 2998621-st square number.

8991727901641 is the 1499311-st centered octagonal number.

It is an amenable number.

8991727901641 is a deficient number, since it is larger than the sum of its proper divisors (125083619180).

8991727901641 is an frugal number, since it uses more digits than its factorization.

8991727901641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82300 (or 41150 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 64.

Multiplying 8991727901641 by its sum of digits (64), we get a square (575470585705024 = 23988968²).

The spelling of 8991727901641 in words is "eight trillion, nine hundred ninety-one billion, seven hundred twenty-seven million, nine hundred one thousand, six hundred forty-one".