81908471 has 2 divisors, whose sum is σ = 81908472. Its totient is φ = 81908470.

The previous prime is 81908459. The next prime is 81908483. The reversal of 81908471 is 17480918.

It is a balanced prime because it is at equal distance from previous prime (81908459) and next prime (81908483).

It is a cyclic number.

It is not a de Polignac number, because 81908471 - 2¹⁰ = 81907447 is a prime.

It is a super-3 number, since 3×81908471³ (a number of 25 digits) contains 333 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 (81901471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40954235 + 40954236.

It is an arithmetic number, because the mean of its divisors is an integer number (40954236).

Almost surely, 2^81908471 is an apocalyptic number.

81908471 is a deficient number, since it is larger than the sum of its proper divisors (1).

81908471 is an equidigital number, since it uses as much as digits as its factorization.

81908471 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 81908471 is about 9050.3298834904. The cubic root of 81908471 is about 434.2864436624.

It can be divided in two parts, 8190 and 8471, that added together give a palindrome (16661).

The spelling of 81908471 in words is "eighty-one million, nine hundred eight thousand, four hundred seventy-one".