20438989 has 2 divisors, whose sum is σ = 20438990. Its totient is φ = 20438988.

The previous prime is 20438933. The next prime is 20439007. The reversal of 20438989 is 98983402.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18774889 + 1664100 = 4333^2 + 1290^2 .

It is a cyclic number.

It is not a de Polignac number, because 20438989 - 2²¹ = 18341837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20438909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10219494 + 10219495.

It is an arithmetic number, because the mean of its divisors is an integer number (10219495).

Almost surely, 2^20438989 is an apocalyptic number.

It is an amenable number.

20438989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20438989 is an equidigital number, since it uses as much as digits as its factorization.

20438989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 20438989 is about 4520.9500107831. The cubic root of 20438989 is about 273.4134048907.

It can be divided in two parts, 204 and 38989, that added together give a palindrome (39193).

The spelling of 20438989 in words is "twenty million, four hundred thirty-eight thousand, nine hundred eighty-nine".