661036331 has 2 divisors, whose sum is σ = 661036332. Its totient is φ = 661036330.

The previous prime is 661036309. The next prime is 661036351. The reversal of 661036331 is 133630166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661036331 - 2¹⁸ = 660774187 is a prime.

It is a super-2 number, since 2×661036331² = 873938061803883122, 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 = 661036294 and 661036303.

It is not a weakly prime, because it can be changed into another prime (661036301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330518165 + 330518166.

It is an arithmetic number, because the mean of its divisors is an integer number (330518166).

Almost surely, 2^661036331 is an apocalyptic number.

661036331 is a deficient number, since it is larger than the sum of its proper divisors (1).

661036331 is an equidigital number, since it uses as much as digits as its factorization.

661036331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 29.

The square root of 661036331 is about 25710.6268107178. The cubic root of 661036331 is about 871.1142331709.

Adding to 661036331 its reverse (133630166), we get a palindrome (794666497).

The spelling of 661036331 in words is "six hundred sixty-one million, thirty-six thousand, three hundred thirty-one".