201661615503 has 72 divisors (see below), whose sum is σ = 312837454800. Its totient is φ = 124832586240.

The previous prime is 201661615487. The next prime is 201661615513. The reversal of 201661615503 is 305516166102.

201661615503 is a `hidden beast` number, since 20 + 1 + 6 + 616 + 15 + 5 + 0 + 3 = 666.

It is not a de Polignac number, because 201661615503 - 2⁴ = 201661615487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201661615513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 354413803 + ... + 354414371.

It is an arithmetic number, because the mean of its divisors is an integer number (4344964650).

Almost surely, 2^201661615503 is an apocalyptic number.

201661615503 is a deficient number, since it is larger than the sum of its proper divisors (111175839297).

201661615503 is a wasteful number, since it uses less digits than its factorization.

201661615503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1273 (or 1209 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 201661615503 in words is "two hundred one billion, six hundred sixty-one million, six hundred fifteen thousand, five hundred three".