20779949 has 4 divisors (see below), whose sum is σ = 20789436. Its totient is φ = 20770464.

The previous prime is 20779937. The next prime is 20779973. The reversal of 20779949 is 94997702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3822025 + 16957924 = 1955^2 + 4118^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20779949 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 (20779919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407 + ... + 6459.

It is an arithmetic number, because the mean of its divisors is an integer number (5197359).

Almost surely, 2^20779949 is an apocalyptic number.

It is an amenable number.

20779949 is a deficient number, since it is larger than the sum of its proper divisors (9487).

20779949 is an equidigital number, since it uses as much as digits as its factorization.

20779949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9486.

The product of its (nonzero) digits is 285768, while the sum is 47.

The square root of 20779949 is about 4558.5029340782. The cubic root of 20779949 is about 274.9253747925.

The spelling of 20779949 in words is "twenty million, seven hundred seventy-nine thousand, nine hundred forty-nine".