28157861842 has 24 divisors (see below), whose sum is σ = 46557224028. Its totient is φ = 12762731520.

The previous prime is 28157861827. The next prime is 28157861843. The reversal of 28157861842 is 24816875182.

It can be written as a sum of positive squares in 2 ways, for example, as 26464457041 + 1693404801 = 162679^2 + 41151^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28157861842.

It is not an unprimeable number, because it can be changed into a prime (28157861843) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 79383 + ... + 250234.

Almost surely, 2^28157861842 is an apocalyptic number.

28157861842 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

28157861842 is a deficient number, since it is larger than the sum of its proper divisors (18399362186).

28157861842 is a wasteful number, since it uses less digits than its factorization.

28157861842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329994 (or 329983 counting only the distinct ones).

The product of its digits is 1720320, while the sum is 52.

The spelling of 28157861842 in words is "twenty-eight billion, one hundred fifty-seven million, eight hundred sixty-one thousand, eight hundred forty-two".