47731991 has 4 divisors (see below), whose sum is σ = 48154512. Its totient is φ = 47309472.

The previous prime is 47731949. The next prime is 47732011. The reversal of 47731991 is 19913774.

47731991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 47731991 - 2⁶ = 47731927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (47731891) 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 3 ways as a sum of consecutive naturals, for example, 211091 + ... + 211316.

It is an arithmetic number, because the mean of its divisors is an integer number (12038628).

Almost surely, 2^47731991 is an apocalyptic number.

47731991 is a deficient number, since it is larger than the sum of its proper divisors (422521).

47731991 is a wasteful number, since it uses less digits than its factorization.

47731991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422520.

The product of its digits is 47628, while the sum is 41.

The square root of 47731991 is about 6908.8342721475. The cubic root of 47731991 is about 362.7464603785.

The spelling of 47731991 in words is "forty-seven million, seven hundred thirty-one thousand, nine hundred ninety-one".