4187981 has 6 divisors (see below), whose sum is σ = 4871790. Its totient is φ = 3589656.

The previous prime is 4187971. The next prime is 4187983. The reversal of 4187981 is 1897814.

It can be written as a sum of positive squares in only one way, i.e., 4120900 + 67081 = 2030^2 + 259^2 .

It is a de Polignac number, because none of the positive numbers 2^k-4187981 is a prime.

It is a super-2 number, since 2×4187981² = 35078369712722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4187983) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 42686 + ... + 42783.

It is an arithmetic number, because the mean of its divisors is an integer number (811965).

Almost surely, 2^4187981 is an apocalyptic number.

It is an amenable number.

4187981 is a deficient number, since it is larger than the sum of its proper divisors (683809).

4187981 is an equidigital number, since it uses as much as digits as its factorization.

4187981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85483 (or 85476 counting only the distinct ones).

The product of its digits is 16128, while the sum is 38.

The square root of 4187981 is about 2046.4557165988. The cubic root of 4187981 is about 161.1888143962.

The spelling of 4187981 in words is "four million, one hundred eighty-seven thousand, nine hundred eighty-one".