1987227891 has 24 divisors (see below), whose sum is σ = 3236017680. Its totient is φ = 1204378560.

The previous prime is 1987227833. The next prime is 1987227943.

1987227891 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1987227891 - 2²² = 1983033587 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1987227791) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 300870 + ... + 307403.

It is an arithmetic number, because the mean of its divisors is an integer number (134834070).

Almost surely, 2^1987227891 is an apocalyptic number.

1987227891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1987227891 is a deficient number, since it is larger than the sum of its proper divisors (1248789789).

1987227891 is a wasteful number, since it uses less digits than its factorization.

1987227891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 608304 (or 608287 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 1987227891 is about 44578.3343228524. The cubic root of 1987227891 is about 1257.2333456443.

The spelling of 1987227891 in words is "one billion, nine hundred eighty-seven million, two hundred twenty-seven thousand, eight hundred ninety-one".