661223013 has 12 divisors (see below), whose sum is σ = 969065664. Its totient is φ = 400741000.

The previous prime is 661222999. The next prime is 661223053. The reversal of 661223013 is 310322166.

It is a happy number.

It is not a de Polignac number, because 661223013 - 2⁹ = 661222501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661223053) 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 11 ways as a sum of consecutive naturals, for example, 910413 + ... + 911138.

It is an arithmetic number, because the mean of its divisors is an integer number (80755472).

Almost surely, 2^661223013 is an apocalyptic number.

It is an amenable number.

661223013 is a deficient number, since it is larger than the sum of its proper divisors (307842651).

661223013 is a wasteful number, since it uses less digits than its factorization.

661223013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1821576 (or 1821565 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 661223013 is about 25714.2569987935. The cubic root of 661223013 is about 871.1962286848.

Adding to 661223013 its reverse (310322166), we get a palindrome (971545179).

The spelling of 661223013 in words is "six hundred sixty-one million, two hundred twenty-three thousand, thirteen".