181864390728 has 16 divisors (see below), whose sum is σ = 454660976880. Its totient is φ = 60621463568.

The previous prime is 181864390709. The next prime is 181864390783. The reversal of 181864390728 is 827093468181.

It is a super-4 number, since 4×181864390728⁴ (a number of 46 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3788841450 + ... + 3788841497.

It is an arithmetic number, because the mean of its divisors is an integer number (28416311055).

Almost surely, 2^181864390728 is an apocalyptic number.

It is an amenable number.

181864390728 is an abundant number, since it is smaller than the sum of its proper divisors (272796586152).

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

181864390728 is a wasteful number, since it uses less digits than its factorization.

181864390728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7577682956 (or 7577682952 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 57.

The spelling of 181864390728 in words is "one hundred eighty-one billion, eight hundred sixty-four million, three hundred ninety thousand, seven hundred twenty-eight".