221705345 has 16 divisors (see below), whose sum is σ = 275781888. Its totient is φ = 170987520.

The previous prime is 221705333. The next prime is 221705353. The reversal of 221705345 is 543507122.

It is a happy number.

221705345 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 221705345 - 2⁴ = 221705329 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8705 + ... + 22785.

It is an arithmetic number, because the mean of its divisors is an integer number (17236368).

Almost surely, 2^221705345 is an apocalyptic number.

It is an amenable number.

221705345 is a deficient number, since it is larger than the sum of its proper divisors (54076543).

221705345 is a wasteful number, since it uses less digits than its factorization.

221705345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14200.

The product of its (nonzero) digits is 8400, while the sum is 29.

The square root of 221705345 is about 14889.7731681849. The cubic root of 221705345 is about 605.2368855847.

The spelling of 221705345 in words is "two hundred twenty-one million, seven hundred five thousand, three hundred forty-five".