20605778 has 8 divisors (see below), whose sum is σ = 30977100. Its totient is φ = 10280080.

The previous prime is 20605771. The next prime is 20605789. The reversal of 20605778 is 87750602.

It can be written as a sum of positive squares in 2 ways, for example, as 19035769 + 1570009 = 4363^2 + 1253^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20605771) 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, 10253 + ... + 12096.

Almost surely, 2^20605778 is an apocalyptic number.

20605778 is a deficient number, since it is larger than the sum of its proper divisors (10371322).

20605778 is a wasteful number, since it uses less digits than its factorization.

20605778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22812.

The product of its (nonzero) digits is 23520, while the sum is 35.

The square root of 20605778 is about 4539.3587652883. The cubic root of 20605778 is about 274.1551060290.

The spelling of 20605778 in words is "twenty million, six hundred five thousand, seven hundred seventy-eight".