221520149 has 8 divisors (see below), whose sum is σ = 234681048. Its totient is φ = 208373760.

The previous prime is 221520137. The next prime is 221520151. The reversal of 221520149 is 941025122.

It can be written as a sum of positive squares in 4 ways, for example, as 59136100 + 162384049 = 7690^2 + 12743^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-221520149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221520119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55199 + ... + 59075.

It is an arithmetic number, because the mean of its divisors is an integer number (29335131).

Almost surely, 2^221520149 is an apocalyptic number.

It is an amenable number.

221520149 is a deficient number, since it is larger than the sum of its proper divisors (13160899).

221520149 is a wasteful number, since it uses less digits than its factorization.

221520149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7255.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 221520149 is about 14883.5529696373. The cubic root of 221520149 is about 605.0683154876.

The spelling of 221520149 in words is "two hundred twenty-one million, five hundred twenty thousand, one hundred forty-nine".