18021978364009 has 2 divisors, whose sum is σ = 18021978364010. Its totient is φ = 18021978364008.

The previous prime is 18021978363973. The next prime is 18021978364057. The reversal of 18021978364009 is 90046387912081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17989855688025 + 32122675984 = 4241445^2 + 179228^2 .

It is a cyclic number.

It is not a de Polignac number, because 18021978364009 - 2¹³ = 18021978355817 is a prime.

It is not a weakly prime, because it can be changed into another prime (18021978364609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9010989182004 + 9010989182005.

It is an arithmetic number, because the mean of its divisors is an integer number (9010989182005).

Almost surely, 2^{18021978364009} is an apocalyptic number.

It is an amenable number.

18021978364009 is a deficient number, since it is larger than the sum of its proper divisors (1).

18021978364009 is an equidigital number, since it uses as much as digits as its factorization.

18021978364009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5225472, while the sum is 58.

The spelling of 18021978364009 in words is "eighteen trillion, twenty-one billion, nine hundred seventy-eight million, three hundred sixty-four thousand, nine".