20981798 has 8 divisors (see below), whose sum is σ = 31548720. Its totient is φ = 10465560.

The previous prime is 20981789. The next prime is 20981801. The reversal of 20981798 is 89718902.

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 pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11618 + ... + 13301.

It is an arithmetic number, because the mean of its divisors is an integer number (3943590).

Almost surely, 2^20981798 is an apocalyptic number.

20981798 is a deficient number, since it is larger than the sum of its proper divisors (10566922).

20981798 is a wasteful number, since it uses less digits than its factorization.

20981798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25342.

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

The square root of 20981798 is about 4580.5892634027. The cubic root of 20981798 is about 275.8126835844.

The spelling of 20981798 in words is "twenty million, nine hundred eighty-one thousand, seven hundred ninety-eight".