19915898985 has 24 divisors (see below), whose sum is σ = 34664150664. Its totient is φ = 10577733120.

The previous prime is 19915898983. The next prime is 19915898999. The reversal of 19915898985 is 58989851991.

It can be written as a sum of positive squares in 4 ways, for example, as 5966635536 + 13949263449 = 77244^2 + 118107^2 .

It is not a de Polignac number, because 19915898985 - 2¹ = 19915898983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19915898983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 907362 + ... + 929051.

It is an arithmetic number, because the mean of its divisors is an integer number (1444339611).

Almost surely, 2^19915898985 is an apocalyptic number.

19915898985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19915898985 is a deficient number, since it is larger than the sum of its proper divisors (14748251679).

19915898985 is a wasteful number, since it uses less digits than its factorization.

19915898985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1836665 (or 1836662 counting only the distinct ones).

The product of its digits is 83980800, while the sum is 72.

The spelling of 19915898985 in words is "nineteen billion, nine hundred fifteen million, eight hundred ninety-eight thousand, nine hundred eighty-five".