27981093989 has 2 divisors, whose sum is σ = 27981093990. Its totient is φ = 27981093988.

The previous prime is 27981093967. The next prime is 27981093997. The reversal of 27981093989 is 98939018972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16296564964 + 11684529025 = 127658^2 + 108095^2 .

It is a cyclic number.

It is not a de Polignac number, because 27981093989 - 2²⁰ = 27980045413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27981093919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13990546994 + 13990546995.

It is an arithmetic number, because the mean of its divisors is an integer number (13990546995).

Almost surely, 2^27981093989 is an apocalyptic number.

It is an amenable number.

27981093989 is a deficient number, since it is larger than the sum of its proper divisors (1).

27981093989 is an equidigital number, since it uses as much as digits as its factorization.

27981093989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17635968, while the sum is 65.

The spelling of 27981093989 in words is "twenty-seven billion, nine hundred eighty-one million, ninety-three thousand, nine hundred eighty-nine".