2087981 has 4 divisors (see below), whose sum is σ = 2386272. Its totient is φ = 1789692.

The previous prime is 2087941. The next prime is 2087983. The reversal of 2087981 is 1897802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1897802 = 2 ⋅948901.

It is a cyclic number.

It is not a de Polignac number, because 2087981 - 2¹⁰ = 2086957 is a prime.

It is a super-2 number, since 2×2087981² = 8719329312722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2087983) 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, 149135 + ... + 149148.

It is an arithmetic number, because the mean of its divisors is an integer number (596568).

2^2087981 is an apocalyptic number.

It is an amenable number.

2087981 is a deficient number, since it is larger than the sum of its proper divisors (298291).

2087981 is an equidigital number, since it uses as much as digits as its factorization.

2087981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298290.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 2087981 is about 1444.9847750063. The cubic root of 2087981 is about 127.8131428821.

Subtracting from 2087981 its sum of digits (35), we obtain a triangular number (2087946 = T₂₀₄₃).

The spelling of 2087981 in words is "two million, eighty-seven thousand, nine hundred eighty-one".