20817998 has 8 divisors (see below), whose sum is σ = 32303880. Its totient is φ = 10050040.

The previous prime is 20817991. The next prime is 20818009. The reversal of 20817998 is 89971802.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20817991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179408 + ... + 179523.

It is an arithmetic number, because the mean of its divisors is an integer number (4037985).

Almost surely, 2^20817998 is an apocalyptic number.

20817998 is a deficient number, since it is larger than the sum of its proper divisors (11485882).

20817998 is a wasteful number, since it uses less digits than its factorization.

20817998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358962.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 20817998 is about 4562.6744350216. The cubic root of 20817998 is about 275.0930726286.

The spelling of 20817998 in words is "twenty million, eight hundred seventeen thousand, nine hundred ninety-eight".