81337523 has 2 divisors, whose sum is σ = 81337524. Its totient is φ = 81337522.

The previous prime is 81337519. The next prime is 81337559. The reversal of 81337523 is 32573318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81337523 - 2² = 81337519 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81337523.

It is not a weakly prime, because it can be changed into another prime (81367523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40668761 + 40668762.

It is an arithmetic number, because the mean of its divisors is an integer number (40668762).

Almost surely, 2^81337523 is an apocalyptic number.

81337523 is a deficient number, since it is larger than the sum of its proper divisors (1).

81337523 is an equidigital number, since it uses as much as digits as its factorization.

81337523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 32.

The square root of 81337523 is about 9018.7317844584. The cubic root of 81337523 is about 433.2750165441.

The spelling of 81337523 in words is "eighty-one million, three hundred thirty-seven thousand, five hundred twenty-three".