81491487503 has 2 divisors, whose sum is σ = 81491487504. Its totient is φ = 81491487502.

The previous prime is 81491487437. The next prime is 81491487541. The reversal of 81491487503 is 30578419418.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81491487503 - 2⁸ = 81491487247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81491487593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40745743751 + 40745743752.

It is an arithmetic number, because the mean of its divisors is an integer number (40745743752).

Almost surely, 2^81491487503 is an apocalyptic number.

81491487503 is a deficient number, since it is larger than the sum of its proper divisors (1).

81491487503 is an equidigital number, since it uses as much as digits as its factorization.

81491487503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 967680, while the sum is 50.

The spelling of 81491487503 in words is "eighty-one billion, four hundred ninety-one million, four hundred eighty-seven thousand, five hundred three".