20779778 has 4 divisors (see below), whose sum is σ = 31169670. Its totient is φ = 10389888.

The previous prime is 20779769. The next prime is 20779789. The reversal of 20779778 is 87797702.

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

It can be written as a sum of positive squares in only one way, i.e., 14190289 + 6589489 = 3767^2 + 2567^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5194943 + ... + 5194946.

Almost surely, 2^20779778 is an apocalyptic number.

20779778 is a deficient number, since it is larger than the sum of its proper divisors (10389892).

20779778 is a wasteful number, since it uses less digits than its factorization.

20779778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10389891.

The product of its (nonzero) digits is 345744, while the sum is 47.

The square root of 20779778 is about 4558.4841778819. The cubic root of 20779778 is about 274.9246206622.

The spelling of 20779778 in words is "twenty million, seven hundred seventy-nine thousand, seven hundred seventy-eight".