221663951 has 2 divisors, whose sum is σ = 221663952. Its totient is φ = 221663950.

The previous prime is 221663933. The next prime is 221663971. The reversal of 221663951 is 159366122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221663951 - 2²⁶ = 154555087 is a prime.

It is a zygodrome in base 6.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221663971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110831975 + 110831976.

It is an arithmetic number, because the mean of its divisors is an integer number (110831976).

Almost surely, 2^221663951 is an apocalyptic number.

221663951 is a deficient number, since it is larger than the sum of its proper divisors (1).

221663951 is an equidigital number, since it uses as much as digits as its factorization.

221663951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 35.

The square root of 221663951 is about 14888.3830888381. The cubic root of 221663951 is about 605.1992158644.

The spelling of 221663951 in words is "two hundred twenty-one million, six hundred sixty-three thousand, nine hundred fifty-one".