27731840921 has 2 divisors, whose sum is σ = 27731840922. Its totient is φ = 27731840920.

The previous prime is 27731840897. The next prime is 27731840947. The reversal of 27731840921 is 12904813772.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21614880400 + 6116960521 = 147020^2 + 78211^2 .

It is a cyclic number.

It is not a de Polignac number, because 27731840921 - 2¹⁴ = 27731824537 is a prime.

It is not a weakly prime, because it can be changed into another prime (27731840951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13865920460 + 13865920461.

It is an arithmetic number, because the mean of its divisors is an integer number (13865920461).

Almost surely, 2^27731840921 is an apocalyptic number.

It is an amenable number.

27731840921 is a deficient number, since it is larger than the sum of its proper divisors (1).

27731840921 is an equidigital number, since it uses as much as digits as its factorization.

27731840921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 44.

The spelling of 27731840921 in words is "twenty-seven billion, seven hundred thirty-one million, eight hundred forty thousand, nine hundred twenty-one".