661533313 has 4 divisors (see below), whose sum is σ = 756038080. Its totient is φ = 567028548.

The previous prime is 661533293. The next prime is 661533331. The reversal of 661533313 is 313335166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 661533313 - 2¹³ = 661525121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661533713) 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, 47252373 + ... + 47252386.

It is an arithmetic number, because the mean of its divisors is an integer number (189009520).

Almost surely, 2^661533313 is an apocalyptic number.

It is an amenable number.

661533313 is a deficient number, since it is larger than the sum of its proper divisors (94504767).

661533313 is an equidigital number, since it uses as much as digits as its factorization.

661533313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94504766.

The product of its digits is 14580, while the sum is 31.

The square root of 661533313 is about 25720.2899089415. The cubic root of 661533313 is about 871.3324862500.

Adding to 661533313 its reverse (313335166), we get a palindrome (974868479).

The spelling of 661533313 in words is "six hundred sixty-one million, five hundred thirty-three thousand, three hundred thirteen".