31491143 has 2 divisors, whose sum is σ = 31491144. Its totient is φ = 31491142.

The previous prime is 31491101. The next prime is 31491149. The reversal of 31491143 is 34119413.

It is a strong prime.

It is an emirp because it is prime and its reverse (34119413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31491143 - 2⁶ = 31491079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31491149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15745571 + 15745572.

It is an arithmetic number, because the mean of its divisors is an integer number (15745572).

Almost surely, 2^31491143 is an apocalyptic number.

31491143 is a deficient number, since it is larger than the sum of its proper divisors (1).

31491143 is an equidigital number, since it uses as much as digits as its factorization.

31491143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 26.

The square root of 31491143 is about 5611.6969804151. The cubic root of 31491143 is about 315.7883771097.

The spelling of 31491143 in words is "thirty-one million, four hundred ninety-one thousand, one hundred forty-three".