20178636 has 48 divisors (see below), whose sum is σ = 49641984. Its totient is φ = 6366976.

The previous prime is 20178629. The next prime is 20178647. The reversal of 20178636 is 63687102.

It is a junction number, because it is equal to n+sod(n) for n = 20178597 and 20178606.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30865 + ... + 31511.

It is an arithmetic number, because the mean of its divisors is an integer number (1034208).

Almost surely, 2^20178636 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20178636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24820992).

20178636 is an abundant number, since it is smaller than the sum of its proper divisors (29463348).

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

20178636 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (20178635) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (790).

20178636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790 (or 788 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 20178636 is about 4492.0636682932. The cubic root of 20178636 is about 272.2475219456.

The spelling of 20178636 in words is "twenty million, one hundred seventy-eight thousand, six hundred thirty-six".