1671781087 has 4 divisors (see below), whose sum is σ = 1677226936. Its totient is φ = 1666335240.

The previous prime is 1671781079. The next prime is 1671781093. The reversal of 1671781087 is 7801871761.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1671781087 - 2³ = 1671781079 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1671781057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2722464 + ... + 2723077.

It is an arithmetic number, because the mean of its divisors is an integer number (419306734).

Almost surely, 2^1671781087 is an apocalyptic number.

1671781087 is a deficient number, since it is larger than the sum of its proper divisors (5445849).

1671781087 is an equidigital number, since it uses as much as digits as its factorization.

1671781087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5445848.

The product of its (nonzero) digits is 131712, while the sum is 46.

The square root of 1671781087 is about 40887.4196666897. The cubic root of 1671781087 is about 1186.8426262538.

The spelling of 1671781087 in words is "one billion, six hundred seventy-one million, seven hundred eighty-one thousand, eighty-seven".