21278370571 has 2 divisors, whose sum is σ = 21278370572. Its totient is φ = 21278370570.

The previous prime is 21278370539. The next prime is 21278370601. The reversal of 21278370571 is 17507387212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21278370571 - 2⁵ = 21278370539 is a prime.

It is not a weakly prime, because it can be changed into another prime (21278371571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10639185285 + 10639185286.

It is an arithmetic number, because the mean of its divisors is an integer number (10639185286).

Almost surely, 2^21278370571 is an apocalyptic number.

21278370571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21278370571 is an equidigital number, since it uses as much as digits as its factorization.

21278370571 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 164640, while the sum is 43.

The spelling of 21278370571 in words is "twenty-one billion, two hundred seventy-eight million, three hundred seventy thousand, five hundred seventy-one".