647138215 has 16 divisors (see below), whose sum is σ = 793460448. Its totient is φ = 506503296.

The previous prime is 647138213. The next prime is 647138221. The reversal of 647138215 is 512831746.

647138215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 647138215 - 2¹ = 647138213 is a prime.

It is a super-3 number, since 3×647138215³ (a number of 27 digits) contains 333 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 (647138213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95572 + ... + 102118.

It is an arithmetic number, because the mean of its divisors is an integer number (49591278).

Almost surely, 2^647138215 is an apocalyptic number.

647138215 is a deficient number, since it is larger than the sum of its proper divisors (146322233).

647138215 is a wasteful number, since it uses less digits than its factorization.

647138215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6978.

The product of its digits is 40320, while the sum is 37.

The square root of 647138215 is about 25438.9114350438. The cubic root of 647138215 is about 864.9659580976.

The spelling of 647138215 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, two hundred fifteen".