20885989 has 2 divisors, whose sum is σ = 20885990. Its totient is φ = 20885988.

The previous prime is 20885987. The next prime is 20885993. The reversal of 20885989 is 98958802.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20884900 + 1089 = 4570^2 + 33^2 .

It is a cyclic number.

It is not a de Polignac number, because 20885989 - 2¹ = 20885987 is a prime.

Together with 20885987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20885981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10442994 + 10442995.

It is an arithmetic number, because the mean of its divisors is an integer number (10442995).

Almost surely, 2^20885989 is an apocalyptic number.

It is an amenable number.

20885989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20885989 is an equidigital number, since it uses as much as digits as its factorization.

20885989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 414720, while the sum is 49.

The square root of 20885989 is about 4570.1191450552. The cubic root of 20885989 is about 275.3922292827.

The spelling of 20885989 in words is "twenty million, eight hundred eighty-five thousand, nine hundred eighty-nine".