731531661 has 16 divisors (see below), whose sum is σ = 1131354624. Its totient is φ = 411778224.

The previous prime is 731531623. The next prime is 731531663. The reversal of 731531661 is 166135137.

It is a happy number.

731531661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 731531661 - 2⁷ = 731531533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (731531663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 258555 + ... + 261368.

It is an arithmetic number, because the mean of its divisors is an integer number (70709664).

Almost surely, 2^731531661 is an apocalyptic number.

It is an amenable number.

731531661 is a deficient number, since it is larger than the sum of its proper divisors (399822963).

731531661 is a wasteful number, since it uses less digits than its factorization.

731531661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520000.

The product of its digits is 11340, while the sum is 33.

The square root of 731531661 is about 27046.8419783161. The cubic root of 731531661 is about 901.0406320996.

Adding to 731531661 its reverse (166135137), we get a palindrome (897666798).

The spelling of 731531661 in words is "seven hundred thirty-one million, five hundred thirty-one thousand, six hundred sixty-one".