20439999971 has 2 divisors, whose sum is σ = 20439999972. Its totient is φ = 20439999970.

The previous prime is 20439999967. The next prime is 20440000027. The reversal of 20439999971 is 17999993402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20439999971 - 2² = 20439999967 is a prime.

It is not a weakly prime, because it can be changed into another prime (20439999871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10219999985 + 10219999986.

It is an arithmetic number, because the mean of its divisors is an integer number (10219999986).

Almost surely, 2^20439999971 is an apocalyptic number.

20439999971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20439999971 is an equidigital number, since it uses as much as digits as its factorization.

20439999971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9920232, while the sum is 62.

The spelling of 20439999971 in words is "twenty billion, four hundred thirty-nine million, nine hundred ninety-nine thousand, nine hundred seventy-one".