21170520671 has 2 divisors, whose sum is σ = 21170520672. Its totient is φ = 21170520670.

The previous prime is 21170520653. The next prime is 21170520673. The reversal of 21170520671 is 17602507112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21170520671 - 2²⁶ = 21103411807 is a prime.

Together with 21170520673, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21170520673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585260335 + 10585260336.

It is an arithmetic number, because the mean of its divisors is an integer number (10585260336).

Almost surely, 2^21170520671 is an apocalyptic number.

21170520671 is a deficient number, since it is larger than the sum of its proper divisors (1).

21170520671 is an equidigital number, since it uses as much as digits as its factorization.

21170520671 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5880, while the sum is 32.

The spelling of 21170520671 in words is "twenty-one billion, one hundred seventy million, five hundred twenty thousand, six hundred seventy-one".