661273013 has 2 divisors, whose sum is σ = 661273014. Its totient is φ = 661273012.

The previous prime is 661273007. The next prime is 661273031. The reversal of 661273013 is 310372166.

Together with next prime (661273031) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 529092004 + 132181009 = 23002^2 + 11497^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661273013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661273043) 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 as a sum of consecutive naturals, namely, 330636506 + 330636507.

It is an arithmetic number, because the mean of its divisors is an integer number (330636507).

Almost surely, 2^661273013 is an apocalyptic number.

It is an amenable number.

661273013 is a deficient number, since it is larger than the sum of its proper divisors (1).

661273013 is an equidigital number, since it uses as much as digits as its factorization.

661273013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 661273013 is about 25715.2292037228. The cubic root of 661273013 is about 871.2181873446.

The spelling of 661273013 in words is "six hundred sixty-one million, two hundred seventy-three thousand, thirteen".