21603720701947 has 2 divisors, whose sum is σ = 21603720701948. Its totient is φ = 21603720701946.

The previous prime is 21603720701929. The next prime is 21603720701963. The reversal of 21603720701947 is 74910702730612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21603720701947 - 2⁴³ = 12807627679739 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21603720701947.

It is not a weakly prime, because it can be changed into another prime (21633720701947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801860350973 + 10801860350974.

It is an arithmetic number, because the mean of its divisors is an integer number (10801860350974).

Almost surely, 2^{21603720701947} is an apocalyptic number.

21603720701947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21603720701947 is an equidigital number, since it uses as much as digits as its factorization.

21603720701947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 889056, while the sum is 49.

The spelling of 21603720701947 in words is "twenty-one trillion, six hundred three billion, seven hundred twenty million, seven hundred one thousand, nine hundred forty-seven".