20989541 has 2 divisors, whose sum is σ = 20989542. Its totient is φ = 20989540.

The previous prime is 20989531. The next prime is 20989567. The reversal of 20989541 is 14598902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15602500 + 5387041 = 3950^2 + 2321^2 .

It is a cyclic number.

It is not a de Polignac number, because 20989541 - 2⁶ = 20989477 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20989495 and 20989504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20989531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10494770 + 10494771.

It is an arithmetic number, because the mean of its divisors is an integer number (10494771).

Almost surely, 2^20989541 is an apocalyptic number.

It is an amenable number.

20989541 is a deficient number, since it is larger than the sum of its proper divisors (1).

20989541 is an equidigital number, since it uses as much as digits as its factorization.

20989541 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 20989541 is about 4581.4343823741. The cubic root of 20989541 is about 275.8466075115.

The spelling of 20989541 in words is "twenty million, nine hundred eighty-nine thousand, five hundred forty-one".