102111515221 has 4 divisors (see below), whose sum is σ = 102263241772. Its totient is φ = 101959788672.

The previous prime is 102111515161. The next prime is 102111515227. The reversal of 102111515221 is 122515111201.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122515111201 = 7 ⋅17502158743.

It can be written as a sum of positive squares in 2 ways, for example, as 19596080196 + 82515435025 = 139986^2 + 287255^2 .

It is a cyclic number.

It is not a de Polignac number, because 102111515221 - 2¹⁵ = 102111482453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102111515192 and 102111515201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102111515227) 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 in 3 ways as a sum of consecutive naturals, for example, 75862266 + ... + 75863611.

It is an arithmetic number, because the mean of its divisors is an integer number (25565810443).

Almost surely, 2^102111515221 is an apocalyptic number.

It is an amenable number.

102111515221 is a deficient number, since it is larger than the sum of its proper divisors (151726551).

102111515221 is an equidigital number, since it uses as much as digits as its factorization.

102111515221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151726550.

The product of its (nonzero) digits is 200, while the sum is 22.

Adding to 102111515221 its reverse (122515111201), we get a palindrome (224626626422).

The spelling of 102111515221 in words is "one hundred two billion, one hundred eleven million, five hundred fifteen thousand, two hundred twenty-one".