163581987 has 4 divisors (see below), whose sum is σ = 218109320. Its totient is φ = 109054656.

The previous prime is 163581967. The next prime is 163581989. The reversal of 163581987 is 789185361.

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

It is not a de Polignac number, because 163581987 - 2¹¹ = 163579939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163581989) 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, 27263662 + ... + 27263667.

It is an arithmetic number, because the mean of its divisors is an integer number (54527330).

Almost surely, 2^163581987 is an apocalyptic number.

163581987 is a deficient number, since it is larger than the sum of its proper divisors (54527333).

163581987 is an equidigital number, since it uses as much as digits as its factorization.

163581987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54527332.

The product of its digits is 362880, while the sum is 48.

The square root of 163581987 is about 12789.9173961367. The cubic root of 163581987 is about 546.9049150308.

The spelling of 163581987 in words is "one hundred sixty-three million, five hundred eighty-one thousand, nine hundred eighty-seven".