20778081 has 8 divisors (see below), whose sum is σ = 27728640. Its totient is φ = 13839792.

The previous prime is 20778071. The next prime is 20778083. The reversal of 20778081 is 18087702.

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

It is not a de Polignac number, because 20778081 - 2⁹ = 20777569 is a prime.

It is a super-2 number, since 2×20778081² = 863457300085122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20778083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2160 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (3466080).

Almost surely, 2^20778081 is an apocalyptic number.

It is an amenable number.

20778081 is a deficient number, since it is larger than the sum of its proper divisors (6950559).

20778081 is a wasteful number, since it uses less digits than its factorization.

20778081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6135.

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 20778081 is about 4558.2980376452. The cubic root of 20778081 is about 274.9171364664.

The spelling of 20778081 in words is "twenty million, seven hundred seventy-eight thousand, eighty-one".