47391991 has 2 divisors, whose sum is σ = 47391992. Its totient is φ = 47391990.

The previous prime is 47391979. The next prime is 47391997. The reversal of 47391991 is 19919374.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 47391991 - 2⁵ = 47391959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (47391997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 23695995 + 23695996.

It is an arithmetic number, because the mean of its divisors is an integer number (23695996).

Almost surely, 2^47391991 is an apocalyptic number.

47391991 is a deficient number, since it is larger than the sum of its proper divisors (1).

47391991 is an equidigital number, since it uses as much as digits as its factorization.

47391991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 43.

The square root of 47391991 is about 6884.1841201409. The cubic root of 47391991 is about 361.8831134687.

It can be divided in two parts, 4739 and 1991, that multiplied together give a palindrome (9435349).

The spelling of 47391991 in words is "forty-seven million, three hundred ninety-one thousand, nine hundred ninety-one".