221864651 has 2 divisors, whose sum is σ = 221864652. Its totient is φ = 221864650.

The previous prime is 221864639. The next prime is 221864659. The reversal of 221864651 is 156468122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221864651 - 2²⁶ = 154755787 is a prime.

It is not a weakly prime, because it can be changed into another prime (221864659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110932325 + 110932326.

It is an arithmetic number, because the mean of its divisors is an integer number (110932326).

Almost surely, 2^221864651 is an apocalyptic number.

221864651 is a deficient number, since it is larger than the sum of its proper divisors (1).

221864651 is an equidigital number, since it uses as much as digits as its factorization.

221864651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23040, while the sum is 35.

The square root of 221864651 is about 14895.1217182002. The cubic root of 221864651 is about 605.3818148569.

The spelling of 221864651 in words is "two hundred twenty-one million, eight hundred sixty-four thousand, six hundred fifty-one".