20999823 has 8 divisors (see below), whose sum is σ = 30153648. Its totient is φ = 12922944.

The previous prime is 20999791. The next prime is 20999843. The reversal of 20999823 is 32899902.

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

It is not a de Polignac number, because 20999823 - 2⁵ = 20999791 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999843) 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, 269190 + ... + 269267.

It is an arithmetic number, because the mean of its divisors is an integer number (3769206).

Almost surely, 2^20999823 is an apocalyptic number.

20999823 is a deficient number, since it is larger than the sum of its proper divisors (9153825).

20999823 is a wasteful number, since it uses less digits than its factorization.

20999823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538473.

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 20999823 is about 4582.5563826319. The cubic root of 20999823 is about 275.8916425096.

The spelling of 20999823 in words is "twenty million, nine hundred ninety-nine thousand, eight hundred twenty-three".