221894861 has 2 divisors, whose sum is σ = 221894862. Its totient is φ = 221894860.

The previous prime is 221894843. The next prime is 221894867. The reversal of 221894861 is 168498122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 169780900 + 52113961 = 13030^2 + 7219^2 .

It is a cyclic number.

It is not a de Polignac number, because 221894861 - 2⁶ = 221894797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221894867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110947430 + 110947431.

It is an arithmetic number, because the mean of its divisors is an integer number (110947431).

Almost surely, 2^221894861 is an apocalyptic number.

It is an amenable number.

221894861 is a deficient number, since it is larger than the sum of its proper divisors (1).

221894861 is an equidigital number, since it uses as much as digits as its factorization.

221894861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 41.

The square root of 221894861 is about 14896.1357740858. The cubic root of 221894861 is about 605.4092906993.

It can be divided in two parts, 2218 and 94861, that added together give a palindrome (97079).

The spelling of 221894861 in words is "two hundred twenty-one million, eight hundred ninety-four thousand, eight hundred sixty-one".