21663798238 has 8 divisors (see below), whose sum is σ = 32497981488. Its totient is φ = 10831137744.

The previous prime is 21663798209. The next prime is 21663798259. The reversal of 21663798238 is 83289736612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344431 + ... + 402442.

It is an arithmetic number, because the mean of its divisors is an integer number (4062247686).

Almost surely, 2^21663798238 is an apocalyptic number.

21663798238 is a deficient number, since it is larger than the sum of its proper divisors (10834183250).

21663798238 is a wasteful number, since it uses less digits than its factorization.

21663798238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761378.

The product of its digits is 5225472, while the sum is 55.

The spelling of 21663798238 in words is "twenty-one billion, six hundred sixty-three million, seven hundred ninety-eight thousand, two hundred thirty-eight".