661495744913 has 4 divisors (see below), whose sum is σ = 662842987248. Its totient is φ = 660148502580.

The previous prime is 661495744901. The next prime is 661495744939. The reversal of 661495744913 is 319447594166.

It is a happy number.

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 a de Polignac number, because none of the positive numbers 2^k-661495744913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661495744993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 673620431 + ... + 673621412.

It is an arithmetic number, because the mean of its divisors is an integer number (165710746812).

Almost surely, 2^661495744913 is an apocalyptic number.

It is an amenable number.

661495744913 is a deficient number, since it is larger than the sum of its proper divisors (1347242335).

661495744913 is a wasteful number, since it uses less digits than its factorization.

661495744913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1347242334.

The product of its digits is 19595520, while the sum is 59.

The spelling of 661495744913 in words is "six hundred sixty-one billion, four hundred ninety-five million, seven hundred forty-four thousand, nine hundred thirteen".