21278371571 has 2 divisors, whose sum is σ = 21278371572. Its totient is φ = 21278371570.

The previous prime is 21278371559. The next prime is 21278371601. The reversal of 21278371571 is 17517387212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21278371571 is a prime.

It is not a weakly prime, because it can be changed into another prime (21278370571) 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, 10639185785 + 10639185786.

It is an arithmetic number, because the mean of its divisors is an integer number (10639185786).

Almost surely, 2^21278371571 is an apocalyptic number.

21278371571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21278371571 is an equidigital number, since it uses as much as digits as its factorization.

21278371571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 164640, while the sum is 44.

The spelling of 21278371571 in words is "twenty-one billion, two hundred seventy-eight million, three hundred seventy-one thousand, five hundred seventy-one".