661541053099 has 4 divisors (see below), whose sum is σ = 669914990560. Its totient is φ = 653167115640.

The previous prime is 661541053051. The next prime is 661541053169. The reversal of 661541053099 is 990350145166.

661541053099 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 990350145166 = 2 ⋅495175072583.

It is a cyclic number.

It is not a de Polignac number, because 661541053099 - 2²¹ = 661538955947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661541053009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4186968612 + ... + 4186968769.

It is an arithmetic number, because the mean of its divisors is an integer number (167478747640).

Almost surely, 2^661541053099 is an apocalyptic number.

661541053099 is a deficient number, since it is larger than the sum of its proper divisors (8373937461).

661541053099 is an equidigital number, since it uses as much as digits as its factorization.

661541053099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8373937460.

The product of its (nonzero) digits is 874800, while the sum is 49.

The spelling of 661541053099 in words is "six hundred sixty-one billion, five hundred forty-one million, fifty-three thousand, ninety-nine".