20989543 has 8 divisors (see below), whose sum is σ = 22286880. Its totient is φ = 19699200.

The previous prime is 20989541. The next prime is 20989567. The reversal of 20989543 is 34598902.

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 20989543 - 2¹ = 20989541 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20989496 and 20989505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989541) 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, 5278 + ... + 8356.

It is an arithmetic number, because the mean of its divisors is an integer number (2785860).

Almost surely, 2^20989543 is an apocalyptic number.

20989543 is a deficient number, since it is larger than the sum of its proper divisors (1297337).

20989543 is a wasteful number, since it uses less digits than its factorization.

20989543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3497.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 20989543 is about 4581.4346006464. The cubic root of 20989543 is about 275.8466162729.

The spelling of 20989543 in words is "twenty million, nine hundred eighty-nine thousand, five hundred forty-three".