18291020728 has 24 divisors (see below), whose sum is σ = 34653015000. Its totient is φ = 9051189504.

The previous prime is 18291020677. The next prime is 18291020731. The reversal of 18291020728 is 82702019281.

It is a super-2 number, since 2×18291020728² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 46228 + ... + 196771.

It is an arithmetic number, because the mean of its divisors is an integer number (1443875625).

Almost surely, 2^18291020728 is an apocalyptic number.

It is an amenable number.

18291020728 is a deficient number, since it is larger than the sum of its proper divisors (16361994272).

18291020728 is an equidigital number, since it uses as much as digits as its factorization.

18291020728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243199 (or 243098 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 40.

The spelling of 18291020728 in words is "eighteen billion, two hundred ninety-one million, twenty thousand, seven hundred twenty-eight".