21252885691 has 2 divisors, whose sum is σ = 21252885692. Its totient is φ = 21252885690.

The previous prime is 21252885677. The next prime is 21252885721. The reversal of 21252885691 is 19658825212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21252885691 - 2¹⁷ = 21252754619 is a prime.

It is not a weakly prime, because it can be changed into another prime (21252885391) 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, 10626442845 + 10626442846.

It is an arithmetic number, because the mean of its divisors is an integer number (10626442846).

Almost surely, 2^21252885691 is an apocalyptic number.

21252885691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252885691 is an equidigital number, since it uses as much as digits as its factorization.

21252885691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 691200, while the sum is 49.

The spelling of 21252885691 in words is "twenty-one billion, two hundred fifty-two million, eight hundred eighty-five thousand, six hundred ninety-one".