1215500121 has 16 divisors (see below), whose sum is σ = 1964445120. Its totient is φ = 736666560.

The previous prime is 1215500107. The next prime is 1215500183. The reversal of 1215500121 is 1210055121.

It is not a de Polignac number, because 1215500121 - 2⁵ = 1215500089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1215500094 and 1215500103.

It is not an unprimeable number, because it can be changed into a prime (1215500101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2046000 + ... + 2046593.

It is an arithmetic number, because the mean of its divisors is an integer number (122777820).

Almost surely, 2^1215500121 is an apocalyptic number.

1215500121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1215500121 is a deficient number, since it is larger than the sum of its proper divisors (748944999).

1215500121 is a wasteful number, since it uses less digits than its factorization.

1215500121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4092613 (or 4092607 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

The square root of 1215500121 is about 34864.0233048339. The cubic root of 1215500121 is about 1067.2143808957.

Adding to 1215500121 its reverse (1210055121), we get a palindrome (2425555242).

The spelling of 1215500121 in words is "one billion, two hundred fifteen million, five hundred thousand, one hundred twenty-one".