221824979 has 2 divisors, whose sum is σ = 221824980. Its totient is φ = 221824978.

The previous prime is 221824963. The next prime is 221824991. The reversal of 221824979 is 979428122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221824979 - 2⁴ = 221824963 is a prime.

It is not a weakly prime, because it can be changed into another prime (221824909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110912489 + 110912490.

It is an arithmetic number, because the mean of its divisors is an integer number (110912490).

Almost surely, 2^221824979 is an apocalyptic number.

221824979 is a deficient number, since it is larger than the sum of its proper divisors (1).

221824979 is an equidigital number, since it uses as much as digits as its factorization.

221824979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 44.

The square root of 221824979 is about 14893.7899474915. The cubic root of 221824979 is about 605.3457295846.

The spelling of 221824979 in words is "two hundred twenty-one million, eight hundred twenty-four thousand, nine hundred seventy-nine".