18387881077 has 2 divisors, whose sum is σ = 18387881078. Its totient is φ = 18387881076.

The previous prime is 18387881069. The next prime is 18387881081. The reversal of 18387881077 is 77018878381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18259035876 + 128845201 = 135126^2 + 11351^2 .

It is an emirp because it is prime and its reverse (77018878381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18387881077 - 2³ = 18387881069 is a prime.

It is a super-3 number, since 3×18387881077³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18387881777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9193940538 + 9193940539.

It is an arithmetic number, because the mean of its divisors is an integer number (9193940539).

Almost surely, 2^18387881077 is an apocalyptic number.

It is an amenable number.

18387881077 is a deficient number, since it is larger than the sum of its proper divisors (1).

18387881077 is an equidigital number, since it uses as much as digits as its factorization.

18387881077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4214784, while the sum is 58.

The spelling of 18387881077 in words is "eighteen billion, three hundred eighty-seven million, eight hundred eighty-one thousand, seventy-seven".