20021999971 has 2 divisors, whose sum is σ = 20021999972. Its totient is φ = 20021999970.

The previous prime is 20021999969. The next prime is 20021999981. The reversal of 20021999971 is 17999912002.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20021999971 - 2¹ = 20021999969 is a prime.

Together with 20021999969, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20021999941) 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, 10010999985 + 10010999986.

It is an arithmetic number, because the mean of its divisors is an integer number (10010999986).

Almost surely, 2^20021999971 is an apocalyptic number.

20021999971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021999971 is an equidigital number, since it uses as much as digits as its factorization.

20021999971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 183708, while the sum is 49.

The spelling of 20021999971 in words is "twenty billion, twenty-one million, nine hundred ninety-nine thousand, nine hundred seventy-one".