8181631 has 2 divisors, whose sum is σ = 8181632. Its totient is φ = 8181630.

The previous prime is 8181623. The next prime is 8181637. The reversal of 8181631 is 1361818.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8181631 - 2³ = 8181623 is a prime.

It is a super-2 number, since 2×8181631² = 133878171640322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 8181631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8181637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4090815 + 4090816.

It is an arithmetic number, because the mean of its divisors is an integer number (4090816).

Almost surely, 2^8181631 is an apocalyptic number.

8181631 is a deficient number, since it is larger than the sum of its proper divisors (1).

8181631 is an equidigital number, since it uses as much as digits as its factorization.

8181631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 8181631 is about 2860.3550478918. The cubic root of 8181631 is about 201.5022791993.

The spelling of 8181631 in words is "eight million, one hundred eighty-one thousand, six hundred thirty-one".