1215116321 has 4 divisors (see below), whose sum is σ = 1216199472. Its totient is φ = 1214033172.

The previous prime is 1215116299. The next prime is 1215116347. The reversal of 1215116321 is 1236115121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1215116321 - 2⁶ = 1215116257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215116621) 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, 539891 + ... + 542136.

It is an arithmetic number, because the mean of its divisors is an integer number (304049868).

Almost surely, 2^1215116321 is an apocalyptic number.

It is an amenable number.

1215116321 is a deficient number, since it is larger than the sum of its proper divisors (1083151).

1215116321 is a wasteful number, since it uses less digits than its factorization.

1215116321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083150.

The product of its digits is 360, while the sum is 23.

The square root of 1215116321 is about 34858.5186288804. The cubic root of 1215116321 is about 1067.1020430493.

The spelling of 1215116321 in words is "one billion, two hundred fifteen million, one hundred sixteen thousand, three hundred twenty-one".