1861404828 has 12 divisors (see below), whose sum is σ = 4343277960. Its totient is φ = 620468272.

The previous prime is 1861404823. The next prime is 1861404841. The reversal of 1861404828 is 8284041681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1861404828.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861404823) 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 3 ways as a sum of consecutive naturals, for example, 77558523 + ... + 77558546.

It is an arithmetic number, because the mean of its divisors is an integer number (361939830).

Almost surely, 2^1861404828 is an apocalyptic number.

It is an amenable number.

1861404828 is an abundant number, since it is smaller than the sum of its proper divisors (2481873132).

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

1861404828 is a wasteful number, since it uses less digits than its factorization.

1861404828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155117076 (or 155117074 counting only the distinct ones).

The product of its (nonzero) digits is 98304, while the sum is 42.

The square root of 1861404828 is about 43144.0010661969. The cubic root of 1861404828 is about 1230.1184868341.

The spelling of 1861404828 in words is "one billion, eight hundred sixty-one million, four hundred four thousand, eight hundred twenty-eight".