647638381 has 8 divisors (see below), whose sum is σ = 698969600. Its totient is φ = 596523312.

The previous prime is 647638379. The next prime is 647638399. The reversal of 647638381 is 183836746.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 647638381 - 2¹ = 647638379 is a prime.

It is a super-2 number, since 2×647638381² = 838870945088602322, 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 (647638331) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47781 + ... + 59818.

It is an arithmetic number, because the mean of its divisors is an integer number (87371200).

Almost surely, 2^647638381 is an apocalyptic number.

It is an amenable number.

647638381 is a deficient number, since it is larger than the sum of its proper divisors (51331219).

647638381 is a wasteful number, since it uses less digits than its factorization.

647638381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108075.

The product of its digits is 580608, while the sum is 46.

The square root of 647638381 is about 25448.7402635180. The cubic root of 647638381 is about 865.1887415998.

The spelling of 647638381 in words is "six hundred forty-seven million, six hundred thirty-eight thousand, three hundred eighty-one".