20989331 has 4 divisors (see below), whose sum is σ = 22897464. Its totient is φ = 19081200.

The previous prime is 20989321. The next prime is 20989333. The reversal of 20989331 is 13398902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20989331 - 2¹⁰ = 20988307 is a prime.

It is a super-2 number, since 2×20989331² = 881104031655122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20989291 and 20989300.

It is not an unprimeable number, because it can be changed into a prime (20989333) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 954050 + ... + 954071.

It is an arithmetic number, because the mean of its divisors is an integer number (5724366).

Almost surely, 2^20989331 is an apocalyptic number.

20989331 is a deficient number, since it is larger than the sum of its proper divisors (1908133).

20989331 is a wasteful number, since it uses less digits than its factorization.

20989331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1908132.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 20989331 is about 4581.4114637304. The cubic root of 20989331 is about 275.8456875616.

The spelling of 20989331 in words is "twenty million, nine hundred eighty-nine thousand, three hundred thirty-one".