647138689 has 4 divisors (see below), whose sum is σ = 681198640. Its totient is φ = 613078740.

The previous prime is 647138623. The next prime is 647138693. The reversal of 647138689 is 986831746.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 986831746 = 2 ⋅493415873.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647138689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (647136689) 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, 17029947 + ... + 17029984.

It is an arithmetic number, because the mean of its divisors is an integer number (170299660).

Almost surely, 2^647138689 is an apocalyptic number.

It is an amenable number.

647138689 is a deficient number, since it is larger than the sum of its proper divisors (34059951).

647138689 is a wasteful number, since it uses less digits than its factorization.

647138689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34059950.

The product of its digits is 1741824, while the sum is 52.

The square root of 647138689 is about 25438.9207514784. The cubic root of 647138689 is about 864.9661692806.

The spelling of 647138689 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, six hundred eighty-nine".