20801057 has 2 divisors, whose sum is σ = 20801058. Its totient is φ = 20801056.

The previous prime is 20801017. The next prime is 20801059. The reversal of 20801057 is 75010802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12222016 + 8579041 = 3496^2 + 2929^2 .

It is a cyclic number.

It is not a de Polignac number, because 20801057 - 2¹⁰ = 20800033 is a prime.

Together with 20801059, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20801059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10400528 + 10400529.

It is an arithmetic number, because the mean of its divisors is an integer number (10400529).

Almost surely, 2^20801057 is an apocalyptic number.

It is an amenable number.

20801057 is a deficient number, since it is larger than the sum of its proper divisors (1).

20801057 is an equidigital number, since it uses as much as digits as its factorization.

20801057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 20801057 is about 4560.8175802152. The cubic root of 20801057 is about 275.0184318224.

Adding to 20801057 its reverse (75010802), we get a palindrome (95811859).

The spelling of 20801057 in words is "twenty million, eight hundred one thousand, fifty-seven".