221451705 has 64 divisors (see below), whose sum is σ = 416862720. Its totient is φ = 111310848.

The previous prime is 221451667. The next prime is 221451731. The reversal of 221451705 is 507154122.

It is not a de Polignac number, because 221451705 - 2⁶ = 221451641 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 226177 + ... + 227153.

It is an arithmetic number, because the mean of its divisors is an integer number (6513480).

Almost surely, 2^221451705 is an apocalyptic number.

It is an amenable number.

221451705 is a deficient number, since it is larger than the sum of its proper divisors (195411015).

221451705 is a wasteful number, since it uses less digits than its factorization.

221451705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1087 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 27.

The square root of 221451705 is about 14881.2534754301. The cubic root of 221451705 is about 605.0059922454.

The spelling of 221451705 in words is "two hundred twenty-one million, four hundred fifty-one thousand, seven hundred five".