27831221891 has 4 divisors (see below), whose sum is σ = 30361332984. Its totient is φ = 25301110800.

The previous prime is 27831221867. The next prime is 27831221893. The reversal of 27831221891 is 19812213872.

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

It is a cyclic number.

It is not a de Polignac number, because 27831221891 - 2⁶ = 27831221827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27831221893) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1265055530 + ... + 1265055551.

It is an arithmetic number, because the mean of its divisors is an integer number (7590333246).

Almost surely, 2^27831221891 is an apocalyptic number.

27831221891 is a deficient number, since it is larger than the sum of its proper divisors (2530111093).

27831221891 is a wasteful number, since it uses less digits than its factorization.

27831221891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2530111092.

The product of its digits is 96768, while the sum is 44.

The spelling of 27831221891 in words is "twenty-seven billion, eight hundred thirty-one million, two hundred twenty-one thousand, eight hundred ninety-one".