20629970021 has 2 divisors, whose sum is σ = 20629970022. Its totient is φ = 20629970020.

The previous prime is 20629969963. The next prime is 20629970027. The reversal of 20629970021 is 12007992602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19546836100 + 1083133921 = 139810^2 + 32911^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20629970021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20629970027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10314985010 + 10314985011.

It is an arithmetic number, because the mean of its divisors is an integer number (10314985011).

Almost surely, 2^20629970021 is an apocalyptic number.

It is an amenable number.

20629970021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20629970021 is an equidigital number, since it uses as much as digits as its factorization.

20629970021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 38.

The spelling of 20629970021 in words is "twenty billion, six hundred twenty-nine million, nine hundred seventy thousand, twenty-one".