81013523 has 2 divisors, whose sum is σ = 81013524. Its totient is φ = 81013522.

The previous prime is 81013507. The next prime is 81013547. The reversal of 81013523 is 32531018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81013523 - 2⁴ = 81013507 is a prime.

It is not a weakly prime, because it can be changed into another prime (81013573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40506761 + 40506762.

It is an arithmetic number, because the mean of its divisors is an integer number (40506762).

Almost surely, 2^81013523 is an apocalyptic number.

81013523 is a deficient number, since it is larger than the sum of its proper divisors (1).

81013523 is an equidigital number, since it uses as much as digits as its factorization.

81013523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 81013523 is about 9000.7512464238. The cubic root of 81013523 is about 432.6989481980.

The spelling of 81013523 in words is "eighty-one million, thirteen thousand, five hundred twenty-three".