20778101 has 4 divisors (see below), whose sum is σ = 20962092. Its totient is φ = 20594112.

The previous prime is 20778083. The next prime is 20778113. The reversal of 20778101 is 10187702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9394225 + 11383876 = 3065^2 + 3374^2 .

It is a cyclic number.

It is not a de Polignac number, because 20778101 - 2¹⁴ = 20761717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20778151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91826 + ... + 92051.

It is an arithmetic number, because the mean of its divisors is an integer number (5240523).

Almost surely, 2^20778101 is an apocalyptic number.

It is an amenable number.

20778101 is a deficient number, since it is larger than the sum of its proper divisors (183991).

20778101 is a wasteful number, since it uses less digits than its factorization.

20778101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183990.

The product of its (nonzero) digits is 784, while the sum is 26.

The square root of 20778101 is about 4558.3002314459. The cubic root of 20778101 is about 274.9172246738.

The spelling of 20778101 in words is "twenty million, seven hundred seventy-eight thousand, one hundred one".