1216865025 has 84 divisors (see below), whose sum is σ = 2361509568. Its totient is φ = 620563680.

The previous prime is 1216865017. The next prime is 1216865033. The reversal of 1216865025 is 5205686121.

It is an interprime number because it is at equal distance from previous prime (1216865017) and next prime (1216865033).

It is not a de Polignac number, because 1216865025 - 2³ = 1216865017 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 417724 + ... + 420626.

Almost surely, 2^1216865025 is an apocalyptic number.

1216865025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216865025 is a deficient number, since it is larger than the sum of its proper divisors (1144644543).

1216865025 is an equidigital number, since it uses as much as digits as its factorization.

1216865025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2954 (or 2934 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1216865025 is about 34883.5924898798. The cubic root of 1216865025 is about 1067.6136953459.

The spelling of 1216865025 in words is "one billion, two hundred sixteen million, eight hundred sixty-five thousand, twenty-five".