20495556 has 18 divisors (see below), whose sum is σ = 51808302. Its totient is φ = 6831840.

The previous prime is 20495539. The next prime is 20495567. The reversal of 20495556 is 65559402.

It can be written as a sum of positive squares in only one way, i.e., 12744900 + 7750656 = 3570^2 + 2784^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 569321 = 20495556 / (2 + 0 + 4 + 9 + 5 + 5 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 20495556.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 284625 + ... + 284696.

It is an arithmetic number, because the mean of its divisors is an integer number (2878239).

Almost surely, 2^20495556 is an apocalyptic number.

It is an amenable number.

20495556 is an abundant number, since it is smaller than the sum of its proper divisors (31312746).

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

20495556 is a wasteful number, since it uses less digits than its factorization.

20495556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 569331 (or 569326 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 20495556 is about 4527.2017847673. The cubic root of 20495556 is about 273.6654057748.

The spelling of 20495556 in words is "twenty million, four hundred ninety-five thousand, five hundred fifty-six".