661333747 has 4 divisors (see below), whose sum is σ = 661492440. Its totient is φ = 661175056.

The previous prime is 661333721. The next prime is 661333763. The reversal of 661333747 is 747333166.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661333747 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661313747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72922 + ... + 81487.

It is an arithmetic number, because the mean of its divisors is an integer number (165373110).

Almost surely, 2^661333747 is an apocalyptic number.

661333747 is a deficient number, since it is larger than the sum of its proper divisors (158693).

661333747 is a wasteful number, since it uses less digits than its factorization.

661333747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158692.

The product of its digits is 190512, while the sum is 40.

The square root of 661333747 is about 25716.4100721699. The cubic root of 661333747 is about 871.2448586007.

The spelling of 661333747 in words is "six hundred sixty-one million, three hundred thirty-three thousand, seven hundred forty-seven".