81401513 has 2 divisors, whose sum is σ = 81401514. Its totient is φ = 81401512.

The previous prime is 81401501. The next prime is 81401543. The reversal of 81401513 is 31510418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56670784 + 24730729 = 7528^2 + 4973^2 .

It is a cyclic number.

It is not a de Polignac number, because 81401513 - 2¹² = 81397417 is a prime.

It is not a weakly prime, because it can be changed into another prime (81401543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700756 + 40700757.

It is an arithmetic number, because the mean of its divisors is an integer number (40700757).

Almost surely, 2^81401513 is an apocalyptic number.

It is an amenable number.

81401513 is a deficient number, since it is larger than the sum of its proper divisors (1).

81401513 is an equidigital number, since it uses as much as digits as its factorization.

81401513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 81401513 is about 9022.2787032989. The cubic root of 81401513 is about 433.3886090566.

The spelling of 81401513 in words is "eighty-one million, four hundred one thousand, five hundred thirteen".