20213220257 has 2 divisors, whose sum is σ = 20213220258. Its totient is φ = 20213220256.

The previous prime is 20213220241. The next prime is 20213220259. The reversal of 20213220257 is 75202231202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20034703936 + 178516321 = 141544^2 + 13361^2 .

It is a cyclic number.

It is not a de Polignac number, because 20213220257 - 2⁴ = 20213220241 is a prime.

Together with 20213220259, 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 (20213220259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10106610128 + 10106610129.

It is an arithmetic number, because the mean of its divisors is an integer number (10106610129).

Almost surely, 2^20213220257 is an apocalyptic number.

It is an amenable number.

20213220257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20213220257 is an equidigital number, since it uses as much as digits as its factorization.

20213220257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 26.

Adding to 20213220257 its reverse (75202231202), we get a palindrome (95415451459).

The spelling of 20213220257 in words is "twenty billion, two hundred thirteen million, two hundred twenty thousand, two hundred fifty-seven".