9781631 has 2 divisors, whose sum is σ = 9781632. Its totient is φ = 9781630.

The previous prime is 9781609. The next prime is 9781643. The reversal of 9781631 is 1361879.

It is a strong prime.

It is an emirp because it is prime and its reverse (1361879) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9781631 - 2¹⁸ = 9519487 is a prime.

It is a super-2 number, since 2×9781631² = 191360610040322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 9781591 and 9781600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9781661) 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, 4890815 + 4890816.

It is an arithmetic number, because the mean of its divisors is an integer number (4890816).

Almost surely, 2^9781631 is an apocalyptic number.

9781631 is a deficient number, since it is larger than the sum of its proper divisors (1).

9781631 is an equidigital number, since it uses as much as digits as its factorization.

9781631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 9781631 is about 3127.5599114965. The cubic root of 9781631 is about 213.8637077256.

The spelling of 9781631 in words is "nine million, seven hundred eighty-one thousand, six hundred thirty-one".