21604006217587 has 2 divisors, whose sum is σ = 21604006217588. Its totient is φ = 21604006217586.

The previous prime is 21604006217569. The next prime is 21604006217609. The reversal of 21604006217587 is 78571260040612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21604006217587 - 2²³ = 21603997828979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21604006217587.

It is not a weakly prime, because it can be changed into another prime (21604006217527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802003108793 + 10802003108794.

It is an arithmetic number, because the mean of its divisors is an integer number (10802003108794).

Almost surely, 2^{21604006217587} is an apocalyptic number.

21604006217587 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604006217587 is an equidigital number, since it uses as much as digits as its factorization.

21604006217587 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1128960, while the sum is 49.

The spelling of 21604006217587 in words is "twenty-one trillion, six hundred four billion, six million, two hundred seventeen thousand, five hundred eighty-seven".