664497237889 has 9 divisors (see below), whose sum is σ = 705899330371. Its totient is φ = 625396122400.

The previous prime is 664497237883. The next prime is 664497237907. The reversal of 664497237889 is 988732794466.

The square root of 664497237889 is 815167.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 517342140225 + 147155097664 = 719265^2 + 383608^2 .

It is not a de Polignac number, because 664497237889 - 2⁵ = 664497237857 is a prime.

It is a super-2 number, since 2×664497237889² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664497237883) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13833864 + ... + 13881814.

Almost surely, 2^664497237889 is an apocalyptic number.

664497237889 is the 815167-th square number.

664497237889 is the 407584-th centered octagonal number.

It is an amenable number.

664497237889 is a deficient number, since it is larger than the sum of its proper divisors (41402092482).

664497237889 is an frugal number, since it uses more digits than its factorization.

664497237889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95936 (or 47968 counting only the distinct ones).

The product of its digits is 877879296, while the sum is 73.

The spelling of 664497237889 in words is "six hundred sixty-four billion, four hundred ninety-seven million, two hundred thirty-seven thousand, eight hundred eighty-nine".