20421001057 has 2 divisors, whose sum is σ = 20421001058. Its totient is φ = 20421001056.

The previous prime is 20421001037. The next prime is 20421001067. The reversal of 20421001057 is 75010012402.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16282780816 + 4138220241 = 127604^2 + 64329^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421001057 - 2²³ = 20412612449 is a prime.

It is not a weakly prime, because it can be changed into another prime (20421001037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210500528 + 10210500529.

It is an arithmetic number, because the mean of its divisors is an integer number (10210500529).

Almost surely, 2^20421001057 is an apocalyptic number.

It is an amenable number.

20421001057 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421001057 is an equidigital number, since it uses as much as digits as its factorization.

20421001057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 22.

Adding to 20421001057 its reverse (75010012402), we get a palindrome (95431013459).

The spelling of 20421001057 in words is "twenty billion, four hundred twenty-one million, one thousand, fifty-seven".