20989542 has 80 divisors (see below), whose sum is σ = 51628032. Its totient is φ = 5680080.

The previous prime is 20989541. The next prime is 20989567. The reversal of 20989542 is 24598902.

It is a self number, because there is not a number n which added to its sum of digits gives 20989542.

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 39 ways as a sum of consecutive naturals, for example, 446563 + ... + 446609.

Almost surely, 2^20989542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20989542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25814016).

20989542 is an abundant number, since it is smaller than the sum of its proper divisors (30638490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20989542 is an equidigital number, since it uses as much as digits as its factorization.

20989542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 20989542 is about 4581.4344915103. The cubic root of 20989542 is about 275.8466118922.

The spelling of 20989542 in words is "twenty million, nine hundred eighty-nine thousand, five hundred forty-two".