221808705 has 16 divisors (see below), whose sum is σ = 355829760. Its totient is φ = 117986048.

The previous prime is 221808703. The next prime is 221808709. The reversal of 221808705 is 507808122.

It is a cyclic number.

It is not a de Polignac number, because 221808705 - 2¹ = 221808703 is a prime.

It is a super-2 number, since 2×221808705² = 98398203227554050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221808703) 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, 13560 + ... + 25049.

It is an arithmetic number, because the mean of its divisors is an integer number (22239360).

Almost surely, 2^221808705 is an apocalyptic number.

It is an amenable number.

221808705 is a deficient number, since it is larger than the sum of its proper divisors (134021055).

221808705 is a wasteful number, since it uses less digits than its factorization.

221808705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39000.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 221808705 is about 14893.2436023856. The cubic root of 221808705 is about 605.3309256652.

The spelling of 221808705 in words is "two hundred twenty-one million, eight hundred eight thousand, seven hundred five".