20777957 has 2 divisors, whose sum is σ = 20777958. Its totient is φ = 20777956.

The previous prime is 20777951. The next prime is 20777969. The reversal of 20777957 is 75977702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11621281 + 9156676 = 3409^2 + 3026^2 .

It is a cyclic number.

It is not a de Polignac number, because 20777957 - 2⁴ = 20777941 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20777951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10388978 + 10388979.

It is an arithmetic number, because the mean of its divisors is an integer number (10388979).

Almost surely, 2^20777957 is an apocalyptic number.

It is an amenable number.

20777957 is a deficient number, since it is larger than the sum of its proper divisors (1).

20777957 is an equidigital number, since it uses as much as digits as its factorization.

20777957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216090, while the sum is 44.

The square root of 20777957 is about 4558.2844360571. The cubic root of 20777957 is about 274.9165895793.

The spelling of 20777957 in words is "twenty million, seven hundred seventy-seven thousand, nine hundred fifty-seven".