221026645 has 16 divisors (see below), whose sum is σ = 303367680. Its totient is φ = 151438464.

The previous prime is 221026591. The next prime is 221026649. The reversal of 221026645 is 546620122.

221026645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 221026645 - 2⁷ = 221026517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221026649) 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, 71604 + ... + 74626.

It is an arithmetic number, because the mean of its divisors is an integer number (18960480).

Almost surely, 2^221026645 is an apocalyptic number.

It is an amenable number.

221026645 is a deficient number, since it is larger than the sum of its proper divisors (82341035).

221026645 is a wasteful number, since it uses less digits than its factorization.

221026645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5124.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 221026645 is about 14866.9648886382. The cubic root of 221026645 is about 604.6186563876.

Adding to 221026645 its reverse (546620122), we get a palindrome (767646767).

The spelling of 221026645 in words is "two hundred twenty-one million, twenty-six thousand, six hundred forty-five".