81948487 has 2 divisors, whose sum is σ = 81948488. Its totient is φ = 81948486.

The previous prime is 81948481. The next prime is 81948509. The reversal of 81948487 is 78484918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81948487 - 2²³ = 73559879 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81948487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81948481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40974243 + 40974244.

It is an arithmetic number, because the mean of its divisors is an integer number (40974244).

Almost surely, 2^81948487 is an apocalyptic number.

81948487 is a deficient number, since it is larger than the sum of its proper divisors (1).

81948487 is an equidigital number, since it uses as much as digits as its factorization.

81948487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 516096, while the sum is 49.

The square root of 81948487 is about 9052.5403616885. The cubic root of 81948487 is about 434.3571550180.

The spelling of 81948487 in words is "eighty-one million, nine hundred forty-eight thousand, four hundred eighty-seven".