20779705 has 8 divisors (see below), whose sum is σ = 25074504. Its totient is φ = 16531200.

The previous prime is 20779697. The next prime is 20779723. The reversal of 20779705 is 50797702.

It can be written as a sum of positive squares in 4 ways, for example, as 131769 + 20647936 = 363^2 + 4544^2 .

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

It is not a de Polignac number, because 20779705 - 2³ = 20779697 is a prime.

It is a super-3 number, since 3×20779705³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 10576 + ... + 12385.

It is an arithmetic number, because the mean of its divisors is an integer number (3134313).

Almost surely, 2^20779705 is an apocalyptic number.

It is an amenable number.

20779705 is a deficient number, since it is larger than the sum of its proper divisors (4294799).

20779705 is a wasteful number, since it uses less digits than its factorization.

20779705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23147.

The product of its (nonzero) digits is 30870, while the sum is 37.

The square root of 20779705 is about 4558.4761708273. The cubic root of 20779705 is about 274.9242987223.

The spelling of 20779705 in words is "twenty million, seven hundred seventy-nine thousand, seven hundred five".