221661603 has 40 divisors (see below), whose sum is σ = 353683968. Its totient is φ = 138012336.

The previous prime is 221661593. The next prime is 221661611. The reversal of 221661603 is 306166122.

221661603 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221661603 - 2⁵ = 221661571 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (221661673) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 78726 + ... + 81492.

Almost surely, 2^221661603 is an apocalyptic number.

221661603 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

221661603 is a deficient number, since it is larger than the sum of its proper divisors (132022365).

221661603 is a wasteful number, since it uses less digits than its factorization.

221661603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2845 (or 2836 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 221661603 is about 14888.3042352042. The cubic root of 221661603 is about 605.1970789769.

The spelling of 221661603 in words is "two hundred twenty-one million, six hundred sixty-one thousand, six hundred three".