20968999 has 4 divisors (see below), whose sum is σ = 21480480. Its totient is φ = 20457520.

The previous prime is 20968979. The next prime is 20969009. The reversal of 20968999 is 99986902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99986902 = 2 ⋅49993451.

It is a cyclic number.

It is not a de Polignac number, because 20968999 - 2¹¹ = 20966951 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 (20968949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 255679 + ... + 255760.

It is an arithmetic number, because the mean of its divisors is an integer number (5370120).

Almost surely, 2^20968999 is an apocalyptic number.

20968999 is a deficient number, since it is larger than the sum of its proper divisors (511481).

20968999 is an equidigital number, since it uses as much as digits as its factorization.

20968999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511480.

The product of its (nonzero) digits is 629856, while the sum is 52.

The square root of 20968999 is about 4579.1919592871. The cubic root of 20968999 is about 275.7565898124.

The spelling of 20968999 in words is "twenty million, nine hundred sixty-eight thousand, nine hundred ninety-nine".