2661663155503 has 4 divisors (see below), whose sum is σ = 2903632533288. Its totient is φ = 2419693777720.

The previous prime is 2661663155377. The next prime is 2661663155527. The reversal of 2661663155503 is 3055513661662.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2661663155503 - 2²⁹ = 2661126284591 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 (2661663155573) 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, 120984688876 + ... + 120984688897.

It is an arithmetic number, because the mean of its divisors is an integer number (725908133322).

Almost surely, 2^{2661663155503} is an apocalyptic number.

2661663155503 is a deficient number, since it is larger than the sum of its proper divisors (241969377785).

2661663155503 is a wasteful number, since it uses less digits than its factorization.

2661663155503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241969377784.

The product of its (nonzero) digits is 2916000, while the sum is 49.

The spelling of 2661663155503 in words is "two trillion, six hundred sixty-one billion, six hundred sixty-three million, one hundred fifty-five thousand, five hundred three".