221491129 has 2 divisors, whose sum is σ = 221491130. Its totient is φ = 221491128.

The previous prime is 221491121. The next prime is 221491157. The reversal of 221491129 is 921194122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221414400 + 76729 = 14880^2 + 277^2 .

It is a cyclic number.

It is not a de Polignac number, because 221491129 - 2³ = 221491121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221491129.

It is not a weakly prime, because it can be changed into another prime (221491121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110745564 + 110745565.

It is an arithmetic number, because the mean of its divisors is an integer number (110745565).

Almost surely, 2^221491129 is an apocalyptic number.

It is an amenable number.

221491129 is a deficient number, since it is larger than the sum of its proper divisors (1).

221491129 is an equidigital number, since it uses as much as digits as its factorization.

221491129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 31.

The square root of 221491129 is about 14882.5780360796. The cubic root of 221491129 is about 605.0418922338.

The spelling of 221491129 in words is "two hundred twenty-one million, four hundred ninety-one thousand, one hundred twenty-nine".