331561687 has 2 divisors, whose sum is σ = 331561688. Its totient is φ = 331561686.

The previous prime is 331561679. The next prime is 331561717. The reversal of 331561687 is 786165133.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 331561687 - 2³ = 331561679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (331561787) 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, 165780843 + 165780844.

It is an arithmetic number, because the mean of its divisors is an integer number (165780844).

Almost surely, 2^331561687 is an apocalyptic number.

331561687 is a deficient number, since it is larger than the sum of its proper divisors (1).

331561687 is an equidigital number, since it uses as much as digits as its factorization.

331561687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 40.

The square root of 331561687 is about 18208.8354103166. The cubic root of 331561687 is about 692.1307006681.

It can be divided in two parts, 33156 and 1687, that added together give a palindrome (34843).

The spelling of 331561687 in words is "three hundred thirty-one million, five hundred sixty-one thousand, six hundred eighty-seven".