18390029255981 has 2 divisors, whose sum is σ = 18390029255982. Its totient is φ = 18390029255980.

The previous prime is 18390029255963. The next prime is 18390029256013. The reversal of 18390029255981 is 18955292009381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15254062866025 + 3135966389956 = 3905645^2 + 1770866^2 .

It is a cyclic number.

It is not a de Polignac number, because 18390029255981 - 2¹⁰ = 18390029254957 is a prime.

It is a super-2 number, since 2×18390029255981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18390029258981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195014627990 + 9195014627991.

It is an arithmetic number, because the mean of its divisors is an integer number (9195014627991).

Almost surely, 2^{18390029255981} is an apocalyptic number.

It is an amenable number.

18390029255981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18390029255981 is an equidigital number, since it uses as much as digits as its factorization.

18390029255981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13996800, while the sum is 62.

The spelling of 18390029255981 in words is "eighteen trillion, three hundred ninety billion, twenty-nine million, two hundred fifty-five thousand, nine hundred eighty-one".