20021306557 has 12 divisors (see below), whose sum is σ = 23637708480. Its totient is φ = 16904981016.

The previous prime is 20021306537. The next prime is 20021306573. The reversal of 20021306557 is 75560312002.

It is a de Polignac number, because none of the positive numbers 2^k-20021306557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021306537) 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 in 11 ways as a sum of consecutive naturals, for example, 3045957 + ... + 3052522.

It is an arithmetic number, because the mean of its divisors is an integer number (1969809040).

Almost surely, 2^20021306557 is an apocalyptic number.

It is an amenable number.

20021306557 is a deficient number, since it is larger than the sum of its proper divisors (3616401923).

20021306557 is an equidigital number, since it uses as much as digits as its factorization.

20021306557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6098560 (or 6098553 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 31.

Adding to 20021306557 its reverse (75560312002), we get a palindrome (95581618559).

The spelling of 20021306557 in words is "twenty billion, twenty-one million, three hundred six thousand, five hundred fifty-seven".