21173309998 has 4 divisors (see below), whose sum is σ = 31759965000. Its totient is φ = 10586654998.

The previous prime is 21173309959. The next prime is 21173310047. The reversal of 21173309998 is 89990337112.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5293327498 + ... + 5293327501.

It is an arithmetic number, because the mean of its divisors is an integer number (7939991250).

Almost surely, 2^21173309998 is an apocalyptic number.

21173309998 is a deficient number, since it is larger than the sum of its proper divisors (10586655002).

21173309998 is a wasteful number, since it uses less digits than its factorization.

21173309998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10586655001.

The product of its (nonzero) digits is 734832, while the sum is 52.

The spelling of 21173309998 in words is "twenty-one billion, one hundred seventy-three million, three hundred nine thousand, nine hundred ninety-eight".