20980999 has 8 divisors (see below), whose sum is σ = 22631840. Its totient is φ = 19335456.

The previous prime is 20980987. The next prime is 20981027. The reversal of 20980999 is 99908902.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20980999 - 2¹⁵ = 20948231 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 (20980919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11737 + ... + 13405.

It is an arithmetic number, because the mean of its divisors is an integer number (2828980).

Almost surely, 2^20980999 is an apocalyptic number.

20980999 is a deficient number, since it is larger than the sum of its proper divisors (1650841).

20980999 is a wasteful number, since it uses less digits than its factorization.

20980999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2649.

The product of its (nonzero) digits is 104976, while the sum is 46.

The square root of 20980999 is about 4580.5020467193. The cubic root of 20980999 is about 275.8091825001.

The spelling of 20980999 in words is "twenty million, nine hundred eighty thousand, nine hundred ninety-nine".