221953643 has 4 divisors (see below), whose sum is σ = 223005768. Its totient is φ = 220901520.

The previous prime is 221953609. The next prime is 221953679. The reversal of 221953643 is 346359122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221953643 - 2⁶ = 221953579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221953943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525746 + ... + 526167.

It is an arithmetic number, because the mean of its divisors is an integer number (55751442).

Almost surely, 2^221953643 is an apocalyptic number.

221953643 is a deficient number, since it is larger than the sum of its proper divisors (1052125).

221953643 is a wasteful number, since it uses less digits than its factorization.

221953643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1052124.

The product of its digits is 38880, while the sum is 35.

The square root of 221953643 is about 14898.1087054700. The cubic root of 221953643 is about 605.4627454853.

The spelling of 221953643 in words is "two hundred twenty-one million, nine hundred fifty-three thousand, six hundred forty-three".