81539063 has 2 divisors, whose sum is σ = 81539064. Its totient is φ = 81539062.

The previous prime is 81539047. The next prime is 81539099. The reversal of 81539063 is 36093518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81539063 - 2⁴ = 81539047 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81539033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40769531 + 40769532.

It is an arithmetic number, because the mean of its divisors is an integer number (40769532).

Almost surely, 2^81539063 is an apocalyptic number.

81539063 is a deficient number, since it is larger than the sum of its proper divisors (1).

81539063 is an equidigital number, since it uses as much as digits as its factorization.

81539063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 81539063 is about 9029.8982829266. The cubic root of 81539063 is about 433.6325810060.

The spelling of 81539063 in words is "eighty-one million, five hundred thirty-nine thousand, sixty-three".