221210645 has 8 divisors (see below), whose sum is σ = 267144504. Its totient is φ = 175840704.

The previous prime is 221210611. The next prime is 221210669. The reversal of 221210645 is 546012122.

It is a happy number.

221210645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 4355569 + 216855076 = 2087^2 + 14726^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221210645 - 2¹² = 221206549 is a prime.

It is a super-2 number, since 2×221210645² = 97868298922632050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221210645.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140114 + ... + 141683.

It is an arithmetic number, because the mean of its divisors is an integer number (33393063).

Almost surely, 2^221210645 is an apocalyptic number.

It is an amenable number.

221210645 is a deficient number, since it is larger than the sum of its proper divisors (45933859).

221210645 is a wasteful number, since it uses less digits than its factorization.

221210645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281959.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 221210645 is about 14873.1518179571. The cubic root of 221210645 is about 604.7863872600.

Adding to 221210645 its reverse (546012122), we get a palindrome (767222767).

The spelling of 221210645 in words is "two hundred twenty-one million, two hundred ten thousand, six hundred forty-five".