1987818 has 64 divisors (see below), whose sum is σ = 4976640. Its totient is φ = 516672.

The previous prime is 1987789. The next prime is 1987819. The reversal of 1987818 is 8187891.

It is a super-2 number, since 2×1987818² = 7902840802248, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 1987818.

It is not an unprimeable number, because it can be changed into a prime (1987819) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37480 + ... + 37532.

It is an arithmetic number, because the mean of its divisors is an integer number (77760).

2^1987818 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1987818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2488320).

1987818 is an abundant number, since it is smaller than the sum of its proper divisors (2988822).

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

1987818 is a wasteful number, since it uses less digits than its factorization.

1987818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131.

The product of its digits is 32256, while the sum is 42.

The square root of 1987818 is about 1409.8999964536. The cubic root of 1987818 is about 125.7357778829.

The spelling of 1987818 in words is "one million, nine hundred eighty-seven thousand, eight hundred eighteen".