1918172865 has 48 divisors (see below), whose sum is σ = 3574584000. Its totient is φ = 875790720.

The previous prime is 1918172863. The next prime is 1918172881. The reversal of 1918172865 is 5682718191.

It is a happy number.

It is not a de Polignac number, because 1918172865 - 2¹ = 1918172863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1918172863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1100895 + ... + 1102635.

It is an arithmetic number, because the mean of its divisors is an integer number (74470500).

Almost surely, 2^1918172865 is an apocalyptic number.

1918172865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1918172865 is a deficient number, since it is larger than the sum of its proper divisors (1656411135).

1918172865 is a wasteful number, since it uses less digits than its factorization.

1918172865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3262 (or 3255 counting only the distinct ones).

The product of its digits is 241920, while the sum is 48.

The square root of 1918172865 is about 43796.9504075341. The cubic root of 1918172865 is about 1242.4986179975.

The spelling of 1918172865 in words is "one billion, nine hundred eighteen million, one hundred seventy-two thousand, eight hundred sixty-five".