661047545945 has 16 divisors (see below), whose sum is σ = 803408482560. Its totient is φ = 522072255744.

The previous prime is 661047545929. The next prime is 661047545947. The reversal of 661047545945 is 549545740166.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 661047545945 - 2⁴ = 661047545929 is a prime.

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (661047545947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2866094 + ... + 3088136.

It is an arithmetic number, because the mean of its divisors is an integer number (50213030160).

Almost surely, 2^661047545945 is an apocalyptic number.

It is an amenable number.

661047545945 is a deficient number, since it is larger than the sum of its proper divisors (142360936615).

661047545945 is a wasteful number, since it uses less digits than its factorization.

661047545945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229664.

The product of its (nonzero) digits is 18144000, while the sum is 56.

The spelling of 661047545945 in words is "six hundred sixty-one billion, forty-seven million, five hundred forty-five thousand, nine hundred forty-five".