47638721 has 8 divisors (see below), whose sum is σ = 52690344. Its totient is φ = 42785280.

The previous prime is 47638699. The next prime is 47638729. The reversal of 47638721 is 12783674.

47638721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3748096 + 43890625 = 1936^2 + 6625^2 .

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 47638721 - 2¹⁸ = 47376577 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 (47638729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49040 + ... + 50001.

It is an arithmetic number, because the mean of its divisors is an integer number (6586293).

Almost surely, 2^47638721 is an apocalyptic number.

It is an amenable number.

47638721 is a deficient number, since it is larger than the sum of its proper divisors (5051623).

47638721 is a wasteful number, since it uses less digits than its factorization.

47638721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99091.

The product of its digits is 56448, while the sum is 38.

The square root of 47638721 is about 6902.0809181000. The cubic root of 47638721 is about 362.5100331745.

The spelling of 47638721 in words is "forty-seven million, six hundred thirty-eight thousand, seven hundred twenty-one".