20817969 has 8 divisors (see below), whose sum is σ = 28714560. Its totient is φ = 13400016.

The previous prime is 20817959. The next prime is 20817971. The reversal of 20817969 is 96971802.

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

It is not a de Polignac number, because 20817969 - 2¹³ = 20809777 is a prime.

It is a super-2 number, since 2×20817969² = 866775666569922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20817969.

It is not an unprimeable number, because it can be changed into a prime (20817919) 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, 119557 + ... + 119730.

It is an arithmetic number, because the mean of its divisors is an integer number (3589320).

Almost surely, 2^20817969 is an apocalyptic number.

20817969 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20817969 is a deficient number, since it is larger than the sum of its proper divisors (7896591).

20817969 is a wasteful number, since it uses less digits than its factorization.

20817969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239319.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 20817969 is about 4562.6712570598. The cubic root of 20817969 is about 275.0929448914.

The spelling of 20817969 in words is "twenty million, eight hundred seventeen thousand, nine hundred sixty-nine".