661311333 has 24 divisors (see below), whose sum is σ = 964094976. Its totient is φ = 436802400.

The previous prime is 661311293. The next prime is 661311349. The reversal of 661311333 is 333113166.

661311333 is a `hidden beast` number, since 6 + 613 + 1 + 13 + 33 = 666.

It is not a de Polignac number, because 661311333 - 2¹⁶ = 661245797 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661311297 and 661311306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661311533) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 533991 + ... + 535227.

It is an arithmetic number, because the mean of its divisors is an integer number (40170624).

Almost surely, 2^661311333 is an apocalyptic number.

It is an amenable number.

661311333 is a deficient number, since it is larger than the sum of its proper divisors (302783643).

661311333 is a wasteful number, since it uses less digits than its factorization.

661311333 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1745 (or 1742 counting only the distinct ones).

The product of its digits is 2916, while the sum is 27.

The square root of 661311333 is about 25715.9742767020. The cubic root of 661311333 is about 871.2350157122.

Adding to 661311333 its reverse (333113166), we get a palindrome (994424499).

The spelling of 661311333 in words is "six hundred sixty-one million, three hundred eleven thousand, three hundred thirty-three".