20779477 has 2 divisors, whose sum is σ = 20779478. Its totient is φ = 20779476.

The previous prime is 20779469. The next prime is 20779489. The reversal of 20779477 is 77497702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17926756 + 2852721 = 4234^2 + 1689^2 .

It is a cyclic number.

It is not a de Polignac number, because 20779477 - 2³ = 20779469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20779427) 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 as a sum of consecutive naturals, namely, 10389738 + 10389739.

It is an arithmetic number, because the mean of its divisors is an integer number (10389739).

Almost surely, 2^20779477 is an apocalyptic number.

It is an amenable number.

20779477 is a deficient number, since it is larger than the sum of its proper divisors (1).

20779477 is an equidigital number, since it uses as much as digits as its factorization.

20779477 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172872, while the sum is 43.

The square root of 20779477 is about 4558.4511624015. The cubic root of 20779477 is about 274.9232932064.

The spelling of 20779477 in words is "twenty million, seven hundred seventy-nine thousand, four hundred seventy-seven".