18643731390 has 128 divisors (see below), whose sum is σ = 51405373440. Its totient is φ = 4803321600.

The previous prime is 18643731389. The next prime is 18643731397. The reversal of 18643731390 is 9313734681.

18643731390 is a `hidden beast` number, since 1 + 86 + 437 + 3 + 139 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18643731397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6368107 + ... + 6371033.

It is an arithmetic number, because the mean of its divisors is an integer number (401604480).

Almost surely, 2^18643731390 is an apocalyptic number.

18643731390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18643731390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25702686720).

18643731390 is an abundant number, since it is smaller than the sum of its proper divisors (32761642050).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18643731390 is a wasteful number, since it uses less digits than its factorization.

18643731390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3735 (or 3729 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The spelling of 18643731390 in words is "eighteen billion, six hundred forty-three million, seven hundred thirty-one thousand, three hundred ninety".