221325129 has 63 divisors (see below), whose sum is σ = 362713143. Its totient is φ = 134964144.

The previous prime is 221325119. The next prime is 221325131. The reversal of 221325129 is 921523122.

It is a happy number.

The square root of 221325129 is 14877.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 116057529 + 105267600 = 10773^2 + 10260^2 .

It is not a de Polignac number, because 221325129 - 2⁹ = 221324617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221325119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 7631887 + ... + 7631915.

Almost surely, 2^221325129 is an apocalyptic number.

221325129 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

221325129 is the 14877-th square number.

221325129 is the 7439-th centered octagonal number.

It is an amenable number.

221325129 is a deficient number, since it is larger than the sum of its proper divisors (141388014).

221325129 is an frugal number, since it uses more digits than its factorization.

221325129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 51 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The cubic root of 221325129 is about 604.8907017454.

It can be divided in two parts, 22132 and 5129, that added together give a triangular number (27261 = T₂₃₃).

The spelling of 221325129 in words is "two hundred twenty-one million, three hundred twenty-five thousand, one hundred twenty-nine".