1215438157121 has 4 divisors (see below), whose sum is σ = 1216252249812. Its totient is φ = 1214624064432.

The previous prime is 1215438157067. The next prime is 1215438157183. The reversal of 1215438157121 is 1217518345121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 931813743025 + 283624414096 = 965305^2 + 532564^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215438157121 - 2¹⁴ = 1215438140737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215438153121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407044106 + ... + 407047091.

It is an arithmetic number, because the mean of its divisors is an integer number (304063062453).

Almost surely, 2^{1215438157121} is an apocalyptic number.

It is an amenable number.

1215438157121 is a deficient number, since it is larger than the sum of its proper divisors (814092691).

1215438157121 is an equidigital number, since it uses as much as digits as its factorization.

1215438157121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814092690.

The product of its digits is 67200, while the sum is 41.

The spelling of 1215438157121 in words is "one trillion, two hundred fifteen billion, four hundred thirty-eight million, one hundred fifty-seven thousand, one hundred twenty-one".