661325231 has 4 divisors (see below), whose sum is σ = 755800272. Its totient is φ = 566850192.

The previous prime is 661325221. The next prime is 661325237. The reversal of 661325231 is 132523166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661325231 - 2¹⁸ = 661063087 is a prime.

It is a super-2 number, since 2×661325231² = 874702122314406722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661325194 and 661325203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661325237) 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 in 3 ways as a sum of consecutive naturals, for example, 47237510 + ... + 47237523.

It is an arithmetic number, because the mean of its divisors is an integer number (188950068).

Almost surely, 2^661325231 is an apocalyptic number.

661325231 is a deficient number, since it is larger than the sum of its proper divisors (94475041).

661325231 is an equidigital number, since it uses as much as digits as its factorization.

661325231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94475040.

The product of its digits is 6480, while the sum is 29.

The square root of 661325231 is about 25716.2444964268. The cubic root of 661325231 is about 871.2411189089.

Adding to 661325231 its reverse (132523166), we get a palindrome (793848397).

The spelling of 661325231 in words is "six hundred sixty-one million, three hundred twenty-five thousand, two hundred thirty-one".