21508331933 has 4 divisors (see below), whose sum is σ = 23463634848. Its totient is φ = 19553029020.

The previous prime is 21508331927. The next prime is 21508331989. The reversal of 21508331933 is 33913380512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21508331933 - 2⁴ = 21508331917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21508331633) 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, 977651441 + ... + 977651462.

It is an arithmetic number, because the mean of its divisors is an integer number (5865908712).

Almost surely, 2^21508331933 is an apocalyptic number.

It is an amenable number.

21508331933 is a deficient number, since it is larger than the sum of its proper divisors (1955302915).

21508331933 is a wasteful number, since it uses less digits than its factorization.

21508331933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1955302914.

The product of its (nonzero) digits is 58320, while the sum is 38.

The spelling of 21508331933 in words is "twenty-one billion, five hundred eight million, three hundred thirty-one thousand, nine hundred thirty-three".