661813726273 has 12 divisors (see below), whose sum is σ = 774165878640. Its totient is φ = 564099800712.

The previous prime is 661813726261. The next prime is 661813726291. The reversal of 661813726273 is 372627318166.

It is not a de Polignac number, because 661813726273 - 2³³ = 653223791681 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661813726273.

It is not an unprimeable number, because it can be changed into a prime (661813726073) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37718611 + ... + 37736152.

It is an arithmetic number, because the mean of its divisors is an integer number (64513823220).

Almost surely, 2^661813726273 is an apocalyptic number.

It is an amenable number.

661813726273 is a deficient number, since it is larger than the sum of its proper divisors (112352152367).

661813726273 is a wasteful number, since it uses less digits than its factorization.

661813726273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75454956 (or 75454949 counting only the distinct ones).

The product of its digits is 3048192, while the sum is 52.

The spelling of 661813726273 in words is "six hundred sixty-one billion, eight hundred thirteen million, seven hundred twenty-six thousand, two hundred seventy-three".