47656721 has 4 divisors (see below), whose sum is σ = 54464832. Its totient is φ = 40848612.

The previous prime is 47656717. The next prime is 47656727. The reversal of 47656721 is 12765674.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 47656721 - 2² = 47656717 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 (47656727) 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, 3404045 + ... + 3404058.

It is an arithmetic number, because the mean of its divisors is an integer number (13616208).

Almost surely, 2^47656721 is an apocalyptic number.

It is an amenable number.

47656721 is a deficient number, since it is larger than the sum of its proper divisors (6808111).

47656721 is an equidigital number, since it uses as much as digits as its factorization.

47656721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6808110.

The product of its digits is 70560, while the sum is 38.

The square root of 47656721 is about 6903.3847495269. The cubic root of 47656721 is about 362.5556848265. Note that the first 3 decimals are identical.

The spelling of 47656721 in words is "forty-seven million, six hundred fifty-six thousand, seven hundred twenty-one".