661451001613 has 4 divisors (see below), whose sum is σ = 661459049440. Its totient is φ = 661442953788.

The previous prime is 661451001593. The next prime is 661451001709. The reversal of 661451001613 is 316100154166.

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-661451001613 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 (661451005613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3899343 + ... + 4065436.

It is an arithmetic number, because the mean of its divisors is an integer number (165364762360).

Almost surely, 2^661451001613 is an apocalyptic number.

It is an amenable number.

661451001613 is a deficient number, since it is larger than the sum of its proper divisors (8047827).

661451001613 is an equidigital number, since it uses as much as digits as its factorization.

661451001613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8047826.

The product of its (nonzero) digits is 12960, while the sum is 34.

Adding to 661451001613 its reverse (316100154166), we get a palindrome (977551155779).

The spelling of 661451001613 in words is "six hundred sixty-one billion, four hundred fifty-one million, one thousand, six hundred thirteen".