2891378232109 has 4 divisors (see below), whose sum is σ = 3061459304604. Its totient is φ = 2721297159616.

The previous prime is 2891378232101. The next prime is 2891378232131. The reversal of 2891378232109 is 9012328731982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 938567627209 + 1952810604900 = 968797^2 + 1397430^2 .

It is a cyclic number.

It is not a de Polignac number, because 2891378232109 - 2³ = 2891378232101 is a prime.

It is a super-2 number, since 2×2891378232109² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2891378232109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2891378232101) 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 3 ways as a sum of consecutive naturals, for example, 85040536222 + ... + 85040536255.

It is an arithmetic number, because the mean of its divisors is an integer number (765364826151).

Almost surely, 2^{2891378232109} is an apocalyptic number.

It is an amenable number.

2891378232109 is a deficient number, since it is larger than the sum of its proper divisors (170081072495).

2891378232109 is a wasteful number, since it uses less digits than its factorization.

2891378232109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170081072494.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 2891378232109 in words is "two trillion, eight hundred ninety-one billion, three hundred seventy-eight million, two hundred thirty-two thousand, one hundred nine".