21388002601 has 12 divisors (see below), whose sum is σ = 25220746452. Its totient is φ = 18081439488.

The previous prime is 21388002557. The next prime is 21388002637. The reversal of 21388002601 is 10620088312.

It can be written as a sum of positive squares in 2 ways, for example, as 5166159376 + 16221843225 = 71876^2 + 127365^2 .

It is not a de Polignac number, because 21388002601 - 2¹³ = 21387994409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21388002661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2986080 + ... + 2993233.

It is an arithmetic number, because the mean of its divisors is an integer number (2101728871).

Almost surely, 2^21388002601 is an apocalyptic number.

It is an amenable number.

21388002601 is a deficient number, since it is larger than the sum of its proper divisors (3832743851).

21388002601 is an equidigital number, since it uses as much as digits as its factorization.

21388002601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5979400 (or 5979393 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The spelling of 21388002601 in words is "twenty-one billion, three hundred eighty-eight million, two thousand, six hundred one".