65591989 has 4 divisors (see below), whose sum is σ = 65778156. Its totient is φ = 65405824.

The previous prime is 65591987. The next prime is 65591993. The reversal of 65591989 is 98919556.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33443089 + 32148900 = 5783^2 + 5670^2 .

It is a cyclic number.

It is not a de Polignac number, because 65591989 - 2¹ = 65591987 is a prime.

It is a super-2 number, since 2×65591989² = 8604618041952242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65591983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92554 + ... + 93259.

It is an arithmetic number, because the mean of its divisors is an integer number (16444539).

Almost surely, 2^65591989 is an apocalyptic number.

It is an amenable number.

65591989 is a deficient number, since it is larger than the sum of its proper divisors (186167).

65591989 is a wasteful number, since it uses less digits than its factorization.

65591989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186166.

The product of its digits is 874800, while the sum is 52.

The square root of 65591989 is about 8098.8881335650. Note that the first 3 decimals coincide. The cubic root of 65591989 is about 403.2895172826.

The spelling of 65591989 in words is "sixty-five million, five hundred ninety-one thousand, nine hundred eighty-nine".