20778911 has 8 divisors (see below), whose sum is σ = 21300864. Its totient is φ = 20263320.

The previous prime is 20778887. The next prime is 20778937. The reversal of 20778911 is 11987702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20778911 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 (20778991) 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, 5396 + ... + 8406.

It is an arithmetic number, because the mean of its divisors is an integer number (2662608).

Almost surely, 2^20778911 is an apocalyptic number.

20778911 is a deficient number, since it is larger than the sum of its proper divisors (521953).

20778911 is a wasteful number, since it uses less digits than its factorization.

20778911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3181.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 20778911 is about 4558.3890794885. The cubic root of 20778911 is about 274.9207970256.

The spelling of 20778911 in words is "twenty million, seven hundred seventy-eight thousand, nine hundred eleven".