7187981 has 2 divisors, whose sum is σ = 7187982. Its totient is φ = 7187980.

The previous prime is 7187963. The next prime is 7187987. The reversal of 7187981 is 1897817.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6786025 + 401956 = 2605^2 + 634^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7187981 is a prime.

It is a super-2 number, since 2×7187981² = 103334141712722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7187987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3593990 + 3593991.

It is an arithmetic number, because the mean of its divisors is an integer number (3593991).

Almost surely, 2^7187981 is an apocalyptic number.

It is an amenable number.

7187981 is a deficient number, since it is larger than the sum of its proper divisors (1).

7187981 is an equidigital number, since it uses as much as digits as its factorization.

7187981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28224, while the sum is 41.

The square root of 7187981 is about 2681.0410291527. The cubic root of 7187981 is about 192.9903706257.

The spelling of 7187981 in words is "seven million, one hundred eighty-seven thousand, nine hundred eighty-one".