221978705 has 16 divisors (see below), whose sum is σ = 291152064. Its totient is φ = 161472960.

The previous prime is 221978677. The next prime is 221978717. The reversal of 221978705 is 507879122.

It is not a de Polignac number, because 221978705 - 2²⁴ = 205201489 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, 21131 + ... + 29840.

It is an arithmetic number, because the mean of its divisors is an integer number (18197004).

Almost surely, 2^221978705 is an apocalyptic number.

It is an amenable number.

221978705 is a deficient number, since it is larger than the sum of its proper divisors (69173359).

221978705 is a wasteful number, since it uses less digits than its factorization.

221978705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51056.

The product of its (nonzero) digits is 70560, while the sum is 41.

The square root of 221978705 is about 14898.9497952037. The cubic root of 221978705 is about 605.4855333312.

The spelling of 221978705 in words is "two hundred twenty-one million, nine hundred seventy-eight thousand, seven hundred five".