20520171836 has 24 divisors (see below), whose sum is σ = 38722281360. Its totient is φ = 9483004800.

The previous prime is 20520171787. The next prime is 20520171839. The reversal of 20520171836 is 63817102502.

It is a happy number.

It is a super-2 number, since 2×20520171836² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20520171796 and 20520171805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20520171839) 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, 3289595 + ... + 3295826.

It is an arithmetic number, because the mean of its divisors is an integer number (1613428390).

Almost surely, 2^20520171836 is an apocalyptic number.

It is an amenable number.

20520171836 is a deficient number, since it is larger than the sum of its proper divisors (18202109524).

20520171836 is a wasteful number, since it uses less digits than its factorization.

20520171836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6585485 (or 6585483 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 35.

The spelling of 20520171836 in words is "twenty billion, five hundred twenty million, one hundred seventy-one thousand, eight hundred thirty-six".