47639981 has 2 divisors, whose sum is σ = 47639982. Its totient is φ = 47639980.

The previous prime is 47639971. The next prime is 47639987. The reversal of 47639981 is 18993674.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41344900 + 6295081 = 6430^2 + 2509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-47639981 is a prime.

It is a super-2 number, since 2×47639981² = 4539135579360722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (47639987) 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 as a sum of consecutive naturals, namely, 23819990 + 23819991.

It is an arithmetic number, because the mean of its divisors is an integer number (23819991).

Almost surely, 2^47639981 is an apocalyptic number.

It is an amenable number.

47639981 is a deficient number, since it is larger than the sum of its proper divisors (1).

47639981 is an equidigital number, since it uses as much as digits as its factorization.

47639981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 47.

The square root of 47639981 is about 6902.1721943168. The cubic root of 47639981 is about 362.5132291645.

The spelling of 47639981 in words is "forty-seven million, six hundred thirty-nine thousand, nine hundred eighty-one".