221215129 has 2 divisors, whose sum is σ = 221215130. Its totient is φ = 221215128.

The previous prime is 221215073. The next prime is 221215153. The reversal of 221215129 is 921512122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203347600 + 17867529 = 14260^2 + 4227^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221215129 is a prime.

It is a super-2 number, since 2×221215129² = 97872266596973282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (221215199) 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, 110607564 + 110607565.

It is an arithmetic number, because the mean of its divisors is an integer number (110607565).

Almost surely, 2^221215129 is an apocalyptic number.

It is an amenable number.

221215129 is a deficient number, since it is larger than the sum of its proper divisors (1).

221215129 is an equidigital number, since it uses as much as digits as its factorization.

221215129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 25.

The square root of 221215129 is about 14873.3025586115. The cubic root of 221215129 is about 604.7904736273.

The spelling of 221215129 in words is "two hundred twenty-one million, two hundred fifteen thousand, one hundred twenty-nine".