21386939633 has 4 divisors (see below), whose sum is σ = 22124420340. Its totient is φ = 20649458928.

The previous prime is 21386939621. The next prime is 21386939647. The reversal of 21386939633 is 33693968312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11461201249 + 9925738384 = 107057^2 + 99628^2 .

It is a cyclic number.

It is not a de Polignac number, because 21386939633 - 2²⁴ = 21370162417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21386939603) 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 in 3 ways as a sum of consecutive naturals, for example, 368740310 + ... + 368740367.

It is an arithmetic number, because the mean of its divisors is an integer number (5531105085).

Almost surely, 2^21386939633 is an apocalyptic number.

It is an amenable number.

21386939633 is a deficient number, since it is larger than the sum of its proper divisors (737480707).

21386939633 is an equidigital number, since it uses as much as digits as its factorization.

21386939633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737480706.

The product of its digits is 3779136, while the sum is 53.

The spelling of 21386939633 in words is "twenty-one billion, three hundred eighty-six million, nine hundred thirty-nine thousand, six hundred thirty-three".