221212987 has 2 divisors, whose sum is σ = 221212988. Its totient is φ = 221212986.

The previous prime is 221212969. The next prime is 221213009. The reversal of 221212987 is 789212122.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221212987 is a prime.

It is not a weakly prime, because it can be changed into another prime (221212907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110606493 + 110606494.

It is an arithmetic number, because the mean of its divisors is an integer number (110606494).

Almost surely, 2^221212987 is an apocalyptic number.

221212987 is a deficient number, since it is larger than the sum of its proper divisors (1).

221212987 is an equidigital number, since it uses as much as digits as its factorization.

221212987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 34.

The square root of 221212987 is about 14873.2305502201. The cubic root of 221212987 is about 604.7885215828.

The spelling of 221212987 in words is "two hundred twenty-one million, two hundred twelve thousand, nine hundred eighty-seven".