661643323 has 32 divisors (see below), whose sum is σ = 804556800. Its totient is φ = 537398400.

The previous prime is 661643309. The next prime is 661643329. The reversal of 661643323 is 323346166.

It is not a de Polignac number, because 661643323 - 2¹⁷ = 661512251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661643329) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 225993 + ... + 228901.

It is an arithmetic number, because the mean of its divisors is an integer number (25142400).

Almost surely, 2^661643323 is an apocalyptic number.

661643323 is a deficient number, since it is larger than the sum of its proper divisors (142913477).

661643323 is a wasteful number, since it uses less digits than its factorization.

661643323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003.

The product of its digits is 46656, while the sum is 34.

The square root of 661643323 is about 25722.4284040213. The cubic root of 661643323 is about 871.3807831244.

Adding to 661643323 its reverse (323346166), we get a palindrome (984989489).

The spelling of 661643323 in words is "six hundred sixty-one million, six hundred forty-three thousand, three hundred twenty-three".