647138767 has 4 divisors (see below), whose sum is σ = 705969576. Its totient is φ = 588307960.

The previous prime is 647138759. The next prime is 647138797. The reversal of 647138767 is 767831746.

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

It is a cyclic number.

It is not a de Polignac number, because 647138767 - 2³ = 647138759 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 647138767.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647138707) 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, 29415388 + ... + 29415409.

It is an arithmetic number, because the mean of its divisors is an integer number (176492394).

Almost surely, 2^647138767 is an apocalyptic number.

647138767 is a deficient number, since it is larger than the sum of its proper divisors (58830809).

647138767 is a wasteful number, since it uses less digits than its factorization.

647138767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58830808.

The product of its digits is 1185408, while the sum is 49.

The square root of 647138767 is about 25438.9222845623. The cubic root of 647138767 is about 864.9662040323.

The spelling of 647138767 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, seven hundred sixty-seven".