21338205136 has 10 divisors (see below), whose sum is σ = 41342772482. Its totient is φ = 10669102560.

The previous prime is 21338205131. The next prime is 21338205143. The reversal of 21338205136 is 63150283312.

It can be written as a sum of positive squares in only one way, i.e., 21327681600 + 10523536 = 146040^2 + 3244^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21338205131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 666818895 + ... + 666818926.

Almost surely, 2^21338205136 is an apocalyptic number.

It is an amenable number.

21338205136 is a deficient number, since it is larger than the sum of its proper divisors (20004567346).

21338205136 is a wasteful number, since it uses less digits than its factorization.

21338205136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333637829 (or 1333637823 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

Adding to 21338205136 its reverse (63150283312), we get a palindrome (84488488448).

The spelling of 21338205136 in words is "twenty-one billion, three hundred thirty-eight million, two hundred five thousand, one hundred thirty-six".