18278912781 has 24 divisors (see below), whose sum is σ = 27061594560. Its totient is φ = 11882241600.

The previous prime is 18278912759. The next prime is 18278912801. The reversal of 18278912781 is 18721987281.

18278912781 is a `hidden beast` number, since 18 + 278 + 91 + 278 + 1 = 666.

It is not a de Polignac number, because 18278912781 - 2⁷ = 18278912653 is a prime.

It is a super-2 number, since 2×18278912781² (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 (18278912711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 717736 + ... + 742766.

It is an arithmetic number, because the mean of its divisors is an integer number (1127566440).

Almost surely, 2^18278912781 is an apocalyptic number.

It is an amenable number.

18278912781 is a deficient number, since it is larger than the sum of its proper divisors (8782681779).

18278912781 is a wasteful number, since it uses less digits than its factorization.

18278912781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27057 (or 27054 counting only the distinct ones).

The product of its digits is 903168, while the sum is 54.

The spelling of 18278912781 in words is "eighteen billion, two hundred seventy-eight million, nine hundred twelve thousand, seven hundred eighty-one".