1881987 has 4 divisors (see below), whose sum is σ = 2509320. Its totient is φ = 1254656.

The previous prime is 1881983. The next prime is 1881989. The reversal of 1881987 is 7891881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7891881 = 3 ⋅2630627.

It is a cyclic number.

It is not a de Polignac number, because 1881987 - 2² = 1881983 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1881983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 313662 + ... + 313667.

It is an arithmetic number, because the mean of its divisors is an integer number (627330).

2^1881987 is an apocalyptic number.

1881987 is a deficient number, since it is larger than the sum of its proper divisors (627333).

1881987 is an equidigital number, since it uses as much as digits as its factorization.

1881987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627332.

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

The square root of 1881987 is about 1371.8553130706. The cubic root of 1881987 is about 123.4635820653.

The spelling of 1881987 in words is "one million, eight hundred eighty-one thousand, nine hundred eighty-seven".