20320355556 has 36 divisors (see below), whose sum is σ = 51527407932. Its totient is φ = 6752080704.

The previous prime is 20320355521. The next prime is 20320355557. The reversal of 20320355556 is 65555302302.

20320355556 is a `hidden beast` number, since 20 + 32 + 0 + 3 + 55 + 556 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 8946133056 + 11374222500 = 94584^2 + 106650^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a self number, because there is not a number n which added to its sum of digits gives 20320355556.

It is not an unprimeable number, because it can be changed into a prime (20320355557) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 878895 + ... + 901718.

It is an arithmetic number, because the mean of its divisors is an integer number (1431316887).

Almost surely, 2^20320355556 is an apocalyptic number.

It is an amenable number.

20320355556 is an abundant number, since it is smaller than the sum of its proper divisors (31207052376).

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

20320355556 is a wasteful number, since it uses less digits than its factorization.

20320355556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780940 (or 1780935 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 36.

Adding to 20320355556 its reverse (65555302302), we get a palindrome (85875657858).

The spelling of 20320355556 in words is "twenty billion, three hundred twenty million, three hundred fifty-five thousand, five hundred fifty-six".