661512133 has 4 divisors (see below), whose sum is σ = 673993548. Its totient is φ = 649030720.

The previous prime is 661512107. The next prime is 661512197. The reversal of 661512133 is 331215166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 331215166 = 2 ⋅165607583.

It can be written as a sum of positive squares in 2 ways, for example, as 554037444 + 107474689 = 23538^2 + 10367^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661512133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661512433) 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, 6240628 + ... + 6240733.

It is an arithmetic number, because the mean of its divisors is an integer number (168498387).

Almost surely, 2^661512133 is an apocalyptic number.

It is an amenable number.

661512133 is a deficient number, since it is larger than the sum of its proper divisors (12481415).

661512133 is a wasteful number, since it uses less digits than its factorization.

661512133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12481414.

The product of its digits is 3240, while the sum is 28.

The square root of 661512133 is about 25719.8781684517. The cubic root of 661512133 is about 871.3231871371.

Adding to 661512133 its reverse (331215166), we get a palindrome (992727299).

The spelling of 661512133 in words is "six hundred sixty-one million, five hundred twelve thousand, one hundred thirty-three".