20178117828 has 36 divisors (see below), whose sum is σ = 55642689648. Its totient is φ = 6114581040.

The previous prime is 20178117821. The next prime is 20178117863. The reversal of 20178117828 is 82871187102.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (20178117821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25477026 + ... + 25477817.

It is an arithmetic number, because the mean of its divisors is an integer number (1545630268).

Almost surely, 2^20178117828 is an apocalyptic number.

It is an amenable number.

20178117828 is an abundant number, since it is smaller than the sum of its proper divisors (35464571820).

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

20178117828 is a wasteful number, since it uses less digits than its factorization.

20178117828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50954864 (or 50954859 counting only the distinct ones).

The product of its (nonzero) digits is 100352, while the sum is 45.

The spelling of 20178117828 in words is "twenty billion, one hundred seventy-eight million, one hundred seventeen thousand, eight hundred twenty-eight".