21878336971 has 2 divisors, whose sum is σ = 21878336972. Its totient is φ = 21878336970.

The previous prime is 21878336969. The next prime is 21878337071. The reversal of 21878336971 is 17963387812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21878336971 - 2¹ = 21878336969 is a prime.

Together with 21878336969, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21878336941) 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, 10939168485 + 10939168486.

It is an arithmetic number, because the mean of its divisors is an integer number (10939168486).

Almost surely, 2^21878336971 is an apocalyptic number.

21878336971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21878336971 is an equidigital number, since it uses as much as digits as its factorization.

21878336971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3048192, while the sum is 55.

The spelling of 21878336971 in words is "twenty-one billion, eight hundred seventy-eight million, three hundred thirty-six thousand, nine hundred seventy-one".