2691823681 has 4 divisors (see below), whose sum is σ = 2728698052. Its totient is φ = 2654949312.

The previous prime is 2691823669. The next prime is 2691823709. The reversal of 2691823681 is 1863281962.

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 2052543025 + 639280656 = 45305^2 + 25284^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2691823681 is a prime.

It is a super-2 number, since 2×2691823681² = 14491829459184779522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2691823661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18437076 + ... + 18437221.

It is an arithmetic number, because the mean of its divisors is an integer number (682174513).

Almost surely, 2^2691823681 is an apocalyptic number.

It is an amenable number.

2691823681 is a deficient number, since it is larger than the sum of its proper divisors (36874371).

2691823681 is an equidigital number, since it uses as much as digits as its factorization.

2691823681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36874370.

The product of its digits is 248832, while the sum is 46.

The square root of 2691823681 is about 51882.7879069735. The cubic root of 2691823681 is about 1391.0696321490.

The spelling of 2691823681 in words is "two billion, six hundred ninety-one million, eight hundred twenty-three thousand, six hundred eighty-one".