531661665 has 32 divisors (see below), whose sum is σ = 868551552. Its totient is φ = 277632000.

The previous prime is 531661649. The next prime is 531661763. The reversal of 531661665 is 566166135.

It is not a de Polignac number, because 531661665 - 2⁴ = 531661649 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 219310 + ... + 221720.

It is an arithmetic number, because the mean of its divisors is an integer number (27142236).

Almost surely, 2^531661665 is an apocalyptic number.

It is an amenable number.

531661665 is a deficient number, since it is larger than the sum of its proper divisors (336889887).

531661665 is a wasteful number, since it uses less digits than its factorization.

531661665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721.

The product of its digits is 97200, while the sum is 39.

The square root of 531661665 is about 23057.7896815805. The cubic root of 531661665 is about 810.1120939214.

The spelling of 531661665 in words is "five hundred thirty-one million, six hundred sixty-one thousand, six hundred sixty-five".