20815361840 has 320 divisors, whose sum is σ = 63752586240. Its totient is φ = 6136197120.

The previous prime is 20815361803. The next prime is 20815361851. The reversal of 20815361840 is 4816351802.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 20815361794 and 20815361803.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8436287 + ... + 8438753.

It is an arithmetic number, because the mean of its divisors is an integer number (199226832).

Almost surely, 2^20815361840 is an apocalyptic number.

20815361840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20815361840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31876293120).

20815361840 is an abundant number, since it is smaller than the sum of its proper divisors (42937224400).

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

20815361840 is a wasteful number, since it uses less digits than its factorization.

20815361840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2580 (or 2574 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 38.

The spelling of 20815361840 in words is "twenty billion, eight hundred fifteen million, three hundred sixty-one thousand, eight hundred forty".