47728721 has 2 divisors, whose sum is σ = 47728722. Its totient is φ = 47728720.

The previous prime is 47728711. The next prime is 47728729. The reversal of 47728721 is 12782774.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47458321 + 270400 = 6889^2 + 520^2 .

It is a cyclic number.

It is not a de Polignac number, because 47728721 - 2²² = 43534417 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (47728729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 23864360 + 23864361.

It is an arithmetic number, because the mean of its divisors is an integer number (23864361).

Almost surely, 2^47728721 is an apocalyptic number.

It is an amenable number.

47728721 is a deficient number, since it is larger than the sum of its proper divisors (1).

47728721 is an equidigital number, since it uses as much as digits as its factorization.

47728721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43904, while the sum is 38.

The square root of 47728721 is about 6908.5976145669. The cubic root of 47728721 is about 362.7381765700.

The spelling of 47728721 in words is "forty-seven million, seven hundred twenty-eight thousand, seven hundred twenty-one".