161553503 has 2 divisors, whose sum is σ = 161553504. Its totient is φ = 161553502.

The previous prime is 161553481. The next prime is 161553517. The reversal of 161553503 is 305355161.

161553503 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (305355161) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161553503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161553563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80776751 + 80776752.

It is an arithmetic number, because the mean of its divisors is an integer number (80776752).

Almost surely, 2^161553503 is an apocalyptic number.

161553503 is a deficient number, since it is larger than the sum of its proper divisors (1).

161553503 is an equidigital number, since it uses as much as digits as its factorization.

161553503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6750, while the sum is 29.

The square root of 161553503 is about 12710.3699002035. The cubic root of 161553503 is about 544.6348905481.

The spelling of 161553503 in words is "one hundred sixty-one million, five hundred fifty-three thousand, five hundred three".