221536491 has 16 divisors (see below), whose sum is σ = 323103360. Its totient is φ = 133902720.

The previous prime is 221536463. The next prime is 221536517. The reversal of 221536491 is 194635122.

221536491 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 221536491 - 2⁵ = 221536459 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (221535491) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3651 + ... + 21363.

It is an arithmetic number, because the mean of its divisors is an integer number (20193960).

Almost surely, 2^221536491 is an apocalyptic number.

221536491 is a deficient number, since it is larger than the sum of its proper divisors (101566869).

221536491 is a wasteful number, since it uses less digits than its factorization.

221536491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18106.

The product of its digits is 12960, while the sum is 33.

The square root of 221536491 is about 14884.1019547704. The cubic root of 221536491 is about 605.0831941692.

The spelling of 221536491 in words is "two hundred twenty-one million, five hundred thirty-six thousand, four hundred ninety-one".