21170525641 has 2 divisors, whose sum is σ = 21170525642. Its totient is φ = 21170525640.

The previous prime is 21170525639. The next prime is 21170525659. The reversal of 21170525641 is 14652507112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15624000016 + 5546525625 = 124996^2 + 74475^2 .

It is a cyclic number.

It is not a de Polignac number, because 21170525641 - 2¹ = 21170525639 is a prime.

Together with 21170525639, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21170525597 and 21170525606.

It is not a weakly prime, because it can be changed into another prime (21170525681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585262820 + 10585262821.

It is an arithmetic number, because the mean of its divisors is an integer number (10585262821).

Almost surely, 2^21170525641 is an apocalyptic number.

It is an amenable number.

21170525641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21170525641 is an equidigital number, since it uses as much as digits as its factorization.

21170525641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 34.

The spelling of 21170525641 in words is "twenty-one billion, one hundred seventy million, five hundred twenty-five thousand, six hundred forty-one".