18081207781 has 16 divisors (see below), whose sum is σ = 22324927744. Its totient is φ = 14260281984.

The previous prime is 18081207779. The next prime is 18081207799. The reversal of 18081207781 is 18770218081.

It is not a de Polignac number, because 18081207781 - 2¹ = 18081207779 is a prime.

It is a super-2 number, since 2×18081207781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18081207181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 288921 + ... + 345886.

It is an arithmetic number, because the mean of its divisors is an integer number (1395307984).

Almost surely, 2^18081207781 is an apocalyptic number.

It is an amenable number.

18081207781 is a deficient number, since it is larger than the sum of its proper divisors (4243719963).

18081207781 is a wasteful number, since it uses less digits than its factorization.

18081207781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635140.

The product of its (nonzero) digits is 50176, while the sum is 43.

The spelling of 18081207781 in words is "eighteen billion, eighty-one million, two hundred seven thousand, seven hundred eighty-one".