2947638721 has 8 divisors (see below), whose sum is σ = 3128146560. Its totient is φ = 2767921728.

The previous prime is 2947638649. The next prime is 2947638731. The reversal of 2947638721 is 1278367492.

It is a happy number.

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 2947638721 - 2²⁹ = 2410767809 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2947638731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 190021 + ... + 204946.

It is an arithmetic number, because the mean of its divisors is an integer number (391018320).

Almost surely, 2^2947638721 is an apocalyptic number.

It is an amenable number.

2947638721 is a deficient number, since it is larger than the sum of its proper divisors (180507839).

2947638721 is a wasteful number, since it uses less digits than its factorization.

2947638721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395423.

The product of its digits is 1016064, while the sum is 49.

The square root of 2947638721 is about 54292.1607693044. The cubic root of 2947638721 is about 1433.8093813671.

The spelling of 2947638721 in words is "two billion, nine hundred forty-seven million, six hundred thirty-eight thousand, seven hundred twenty-one".