1215445121 has 6 divisors (see below), whose sum is σ = 1335985266. Its totient is φ = 1104950000.

The previous prime is 1215445093. The next prime is 1215445139.

It is a happy number.

1215445121 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 653518096 + 561927025 = 25564^2 + 23705^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1215445121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1215445151) 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 5 ways as a sum of consecutive naturals, for example, 5022380 + ... + 5022621.

It is an arithmetic number, because the mean of its divisors is an integer number (222664211).

Almost surely, 2^1215445121 is an apocalyptic number.

1215445121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1215445121 is a deficient number, since it is larger than the sum of its proper divisors (120540145).

1215445121 is a wasteful number, since it uses less digits than its factorization.

1215445121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10045023 (or 10045012 counting only the distinct ones).

The product of its digits is 1600, while the sum is 26.

The square root of 1215445121 is about 34863.2345171816. The cubic root of 1215445121 is about 1067.1982839067.

It can be divided in two parts, 12154 and 45121, that added together give a palindrome (57275).

The spelling of 1215445121 in words is "one billion, two hundred fifteen million, four hundred forty-five thousand, one hundred twenty-one".