7851987 has 24 divisors (see below), whose sum is σ = 13326768. Its totient is φ = 4392000.

The previous prime is 7851979. The next prime is 7851989. The reversal of 7851987 is 7891587.

It is not a de Polignac number, because 7851987 - 2³ = 7851979 is a prime.

7851987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7851989) 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 23 ways as a sum of consecutive naturals, for example, 1764 + ... + 4337.

It is an arithmetic number, because the mean of its divisors is an integer number (555282).

Almost surely, 2^7851987 is an apocalyptic number.

7851987 is a deficient number, since it is larger than the sum of its proper divisors (5474781).

7851987 is a wasteful number, since it uses less digits than its factorization.

7851987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6131 (or 6128 counting only the distinct ones).

The product of its digits is 141120, while the sum is 45.

The square root of 7851987 is about 2802.1397181440. The cubic root of 7851987 is about 198.7588722751.

It can be divided in two parts, 78519 and 87, that added together give a triangular number (78606 = T₃₉₆).

The spelling of 7851987 in words is "seven million, eight hundred fifty-one thousand, nine hundred eighty-seven".