221540013 has 12 divisors (see below), whose sum is σ = 320142108. Its totient is φ = 147628800.

The previous prime is 221540009. The next prime is 221540017. The reversal of 221540013 is 310045122.

It is an interprime number because it is at equal distance from previous prime (221540009) and next prime (221540017).

It can be written as a sum of positive squares in 2 ways, for example, as 55980324 + 165559689 = 7482^2 + 12867^2 .

It is not a de Polignac number, because 221540013 - 2² = 221540009 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221540017) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25981 + ... + 33437.

It is an arithmetic number, because the mean of its divisors is an integer number (26678509).

Almost surely, 2^221540013 is an apocalyptic number.

It is an amenable number.

221540013 is a deficient number, since it is larger than the sum of its proper divisors (98602095).

221540013 is a wasteful number, since it uses less digits than its factorization.

221540013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10764 (or 10761 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 221540013 is about 14884.2202684588. The cubic root of 221540013 is about 605.0864007014.

Adding to 221540013 its reverse (310045122), we get a palindrome (531585135).

The spelling of 221540013 in words is "two hundred twenty-one million, five hundred forty thousand, thirteen".