19861842 has 64 divisors (see below), whose sum is σ = 53351424. Its totient is φ = 4760640.

The previous prime is 19861801. The next prime is 19861843. The reversal of 19861842 is 24816891.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 19861842.

It is not an unprimeable number, because it can be changed into a prime (19861843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4353 + ... + 7659.

It is an arithmetic number, because the mean of its divisors is an integer number (833616).

Almost surely, 2^19861842 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19861842, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26675712).

19861842 is an abundant number, since it is smaller than the sum of its proper divisors (33489582).

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

19861842 is a wasteful number, since it uses less digits than its factorization.

19861842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3343.

The product of its digits is 27648, while the sum is 39.

The square root of 19861842 is about 4456.6626527033. The cubic root of 19861842 is about 270.8152860453.

It can be divided in two parts, 1986 and 1842, that added together give a triangular number (3828 = T₈₇).

The spelling of 19861842 in words is "nineteen million, eight hundred sixty-one thousand, eight hundred forty-two".