20816901540 has 72 divisors (see below), whose sum is σ = 66858999480. Its totient is φ = 5224633344.

The previous prime is 20816901499. The next prime is 20816901551. The reversal of 20816901540 is 4510961802.

20816901540 is a `hidden beast` number, since 20 + 8 + 1 + 6 + 90 + 1 + 540 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1585313856 + 19231587684 = 39816^2 + 138678^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20816901495 and 20816901504.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3398395 + ... + 3404514.

It is an arithmetic number, because the mean of its divisors is an integer number (928597215).

Almost surely, 2^20816901540 is an apocalyptic number.

20816901540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20816901540 is an abundant number, since it is smaller than the sum of its proper divisors (46042097940).

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

20816901540 is a wasteful number, since it uses less digits than its factorization.

20816901540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6802941 (or 6802936 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 20816901540 in words is "twenty billion, eight hundred sixteen million, nine hundred one thousand, five hundred forty".