20778563 has 8 divisors (see below), whose sum is σ = 22629600. Its totient is φ = 18963648.

The previous prime is 20778557. The next prime is 20778577. The reversal of 20778563 is 36587702.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20778563 - 2¹⁰ = 20777539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20778763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7823 + ... + 10136.

It is an arithmetic number, because the mean of its divisors is an integer number (2828700).

Almost surely, 2^20778563 is an apocalyptic number.

20778563 is a deficient number, since it is larger than the sum of its proper divisors (1851037).

20778563 is a wasteful number, since it uses less digits than its factorization.

20778563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18061.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 20778563 is about 4558.3509079491. The cubic root of 20778563 is about 274.9192622488.

The spelling of 20778563 in words is "twenty million, seven hundred seventy-eight thousand, five hundred sixty-three".