661131265 has 8 divisors (see below), whose sum is σ = 818949888. Its totient is φ = 511843440.

The previous prime is 661131257. The next prime is 661131283. The reversal of 661131265 is 562131166.

661131265 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661131265 - 2³ = 661131257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2132527 + ... + 2132836.

It is an arithmetic number, because the mean of its divisors is an integer number (102368736).

Almost surely, 2^661131265 is an apocalyptic number.

It is an amenable number.

661131265 is a deficient number, since it is larger than the sum of its proper divisors (157818623).

661131265 is a wasteful number, since it uses less digits than its factorization.

661131265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4265399.

The product of its digits is 6480, while the sum is 31.

The square root of 661131265 is about 25712.4729460237. The cubic root of 661131265 is about 871.1559325431.

Subtracting from 661131265 its reverse (562131166), we obtain a palindrome (99000099).

The spelling of 661131265 in words is "six hundred sixty-one million, one hundred thirty-one thousand, two hundred sixty-five".