1215824865 has 32 divisors (see below), whose sum is σ = 1996348032. Its totient is φ = 631488000.

The previous prime is 1215824861. The next prime is 1215824881. The reversal of 1215824865 is 5684285121.

It is not a de Polignac number, because 1215824865 - 2² = 1215824861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1215824861) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 423535 + ... + 426395.

It is an arithmetic number, because the mean of its divisors is an integer number (62385876).

Almost surely, 2^1215824865 is an apocalyptic number.

1215824865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1215824865 is a deficient number, since it is larger than the sum of its proper divisors (780523167).

1215824865 is a wasteful number, since it uses less digits than its factorization.

1215824865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3601.

The product of its digits is 153600, while the sum is 42.

The square root of 1215824865 is about 34868.6802876163. The cubic root of 1215824865 is about 1067.3094146466.

The spelling of 1215824865 in words is "one billion, two hundred fifteen million, eight hundred twenty-four thousand, eight hundred sixty-five".