999998855172 has 24 divisors (see below), whose sum is σ = 2592589624800. Its totient is φ = 333332951688.

The previous prime is 999998855171. The next prime is 999998855269. The reversal of 999998855172 is 271558899999.

It is a happy number.

999998855172 is a `hidden beast` number, since 9 + 9 + 9 + 9 + 98 + 8 + 5 + 517 + 2 = 666.

It is a super-2 number, since 2×999998855172² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 999998855091 and 999998855100.

It is not an unprimeable number, because it can be changed into a prime (999998855171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4629624222 + ... + 4629624437.

It is an arithmetic number, because the mean of its divisors is an integer number (108024567700).

Almost surely, 2^999998855172 is an apocalyptic number.

It is an amenable number.

999998855172 is an abundant number, since it is smaller than the sum of its proper divisors (1592590769628).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999998855172 is a wasteful number, since it uses less digits than its factorization.

999998855172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9259248672 (or 9259248664 counting only the distinct ones).

The product of its digits is 1322697600, while the sum is 81.

The spelling of 999998855172 in words is "nine hundred ninety-nine billion, nine hundred ninety-eight million, eight hundred fifty-five thousand, one hundred seventy-two".