20865777606 has 96 divisors (see below), whose sum is σ = 49602241920. Its totient is φ = 6497756496.

The previous prime is 20865777497. The next prime is 20865777623. The reversal of 20865777606 is 60677756802.

20865777606 is a `hidden beast` number, since 2 + 0 + 8 + 6 + 577 + 7 + 60 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1219845 + ... + 1236831.

It is an arithmetic number, because the mean of its divisors is an integer number (516690020).

Almost surely, 2^20865777606 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20865777606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24801120960).

20865777606 is an abundant number, since it is smaller than the sum of its proper divisors (28736464314).

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

20865777606 is a wasteful number, since it uses less digits than its factorization.

20865777606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17087 (or 17058 counting only the distinct ones).

The product of its (nonzero) digits is 5927040, while the sum is 54.

The spelling of 20865777606 in words is "twenty billion, eight hundred sixty-five million, seven hundred seventy-seven thousand, six hundred six".