1215952321 has 4 divisors (see below), whose sum is σ = 1216092592. Its totient is φ = 1215812052.

The previous prime is 1215952301. The next prime is 1215952333. The reversal of 1215952321 is 1232595121.

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 1215952321 - 2⁵ = 1215952289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215952301) 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, 56211 + ... + 74776.

It is an arithmetic number, because the mean of its divisors is an integer number (304023148).

Almost surely, 2^1215952321 is an apocalyptic number.

It is an amenable number.

1215952321 is a deficient number, since it is larger than the sum of its proper divisors (140271).

1215952321 is an equidigital number, since it uses as much as digits as its factorization.

1215952321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140270.

The product of its digits is 5400, while the sum is 31.

The square root of 1215952321 is about 34870.5078970754. The cubic root of 1215952321 is about 1067.3467090080.

The spelling of 1215952321 in words is "one billion, two hundred fifteen million, nine hundred fifty-two thousand, three hundred twenty-one".