19989657 has 12 divisors (see below), whose sum is σ = 29654820. Its totient is φ = 12966048.

The previous prime is 19989647. The next prime is 19989689. The reversal of 19989657 is 75698991.

It can be written as a sum of positive squares in 2 ways, for example, as 19395216 + 594441 = 4404^2 + 771^2 .

It is not a de Polignac number, because 19989657 - 2¹¹ = 19987609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19989647) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29682 + ... + 30347.

It is an arithmetic number, because the mean of its divisors is an integer number (2471235).

Almost surely, 2^19989657 is an apocalyptic number.

It is an amenable number.

19989657 is a deficient number, since it is larger than the sum of its proper divisors (9665163).

19989657 is a wasteful number, since it uses less digits than its factorization.

19989657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60072 (or 60069 counting only the distinct ones).

The product of its digits is 1224720, while the sum is 54.

The square root of 19989657 is about 4470.9794229005. The cubic root of 19989657 is about 271.3949615553.

The spelling of 19989657 in words is "nineteen million, nine hundred eighty-nine thousand, six hundred fifty-seven".