81369149 has 2 divisors, whose sum is σ = 81369150. Its totient is φ = 81369148.

The previous prime is 81369139. The next prime is 81369161. The reversal of 81369149 is 94196318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71402500 + 9966649 = 8450^2 + 3157^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81369149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81369109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684574 + 40684575.

It is an arithmetic number, because the mean of its divisors is an integer number (40684575).

Almost surely, 2^81369149 is an apocalyptic number.

It is an amenable number.

81369149 is a deficient number, since it is larger than the sum of its proper divisors (1).

81369149 is an equidigital number, since it uses as much as digits as its factorization.

81369149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 41.

The square root of 81369149 is about 9020.4849647899. The cubic root of 81369149 is about 433.3311652094.

It can be divided in two parts, 81369 and 149, that added together give a palindrome (81518).

The spelling of 81369149 in words is "eighty-one million, three hundred sixty-nine thousand, one hundred forty-nine".