221312045 has 6 divisors (see below), whose sum is σ = 265614378. Its totient is φ = 177023024.

The previous prime is 221312033. The next prime is 221312051. The reversal of 221312045 is 540213122.

221312045 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 3 ways, for example, as 20268004 + 201044041 = 4502^2 + 14179^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221312045 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 29939 + ... + 36591.

It is an arithmetic number, because the mean of its divisors is an integer number (44269063).

Almost surely, 2^221312045 is an apocalyptic number.

It is an amenable number.

221312045 is a deficient number, since it is larger than the sum of its proper divisors (44302333).

221312045 is an frugal number, since it uses more digits than its factorization.

221312045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13311 (or 6658 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 221312045 is about 14876.5602543061. The cubic root of 221312045 is about 604.8787818067.

Multiplying 221312045 by its sum of digits (20), we get a square (4426240900 = 66530²).

Adding to 221312045 its reverse (540213122), we get a palindrome (761525167).

The spelling of 221312045 in words is "two hundred twenty-one million, three hundred twelve thousand, forty-five".