81215850427 has 2 divisors, whose sum is σ = 81215850428. Its totient is φ = 81215850426.

The previous prime is 81215850389. The next prime is 81215850503. The reversal of 81215850427 is 72405851218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81215850427 - 2⁷ = 81215850299 is a prime.

It is not a weakly prime, because it can be changed into another prime (81215853427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40607925213 + 40607925214.

It is an arithmetic number, because the mean of its divisors is an integer number (40607925214).

Almost surely, 2^81215850427 is an apocalyptic number.

81215850427 is a deficient number, since it is larger than the sum of its proper divisors (1).

81215850427 is an equidigital number, since it uses as much as digits as its factorization.

81215850427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 179200, while the sum is 43.

The spelling of 81215850427 in words is "eighty-one billion, two hundred fifteen million, eight hundred fifty thousand, four hundred twenty-seven".