81290507 has 2 divisors, whose sum is σ = 81290508. Its totient is φ = 81290506.

The previous prime is 81290483. The next prime is 81290513. The reversal of 81290507 is 70509218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81290507 - 2¹² = 81286411 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81290207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40645253 + 40645254.

It is an arithmetic number, because the mean of its divisors is an integer number (40645254).

Almost surely, 2^81290507 is an apocalyptic number.

81290507 is a deficient number, since it is larger than the sum of its proper divisors (1).

81290507 is an equidigital number, since it uses as much as digits as its factorization.

81290507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 81290507 is about 9016.1248327649. The cubic root of 81290507 is about 433.1915176303.

It can be divided in two parts, 812 and 90507, that added together give a palindrome (91319).

The spelling of 81290507 in words is "eighty-one million, two hundred ninety thousand, five hundred seven".