2131987 has 16 divisors (see below), whose sum is σ = 2655072.
Its totient is φ = 1681920.
The previous prime is 2131981. The next prime is 2131991. The reversal of 2131987 is 7891312.
It is a cyclic number.
It is not a de Polignac number, because 2131987 - 23 = 2131979 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (2131981) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1993 + ... + 2869.
It is an arithmetic number, because the mean of its divisors is an integer number (165942).
22131987 is an apocalyptic number.
2131987 is a deficient number, since it is larger than the sum of its proper divisors (523085).
2131987 is a wasteful number, since it uses less digits than its factorization.
2131987 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 918.
The product of its digits is 3024, while the sum is 31.
The square root of 2131987 is about 1460.1325282316.
The cubic root of 2131987 is about 128.7048316123.
The spelling of 2131987 in words is "two million, one hundred thirty-one thousand, nine hundred eighty-seven".