81136461 has 48 divisors (see below), whose sum is σ = 136160640. Its totient is φ = 42040320.

The previous prime is 81136459. The next prime is 81136477. The reversal of 81136461 is 16463118.

It is not a de Polignac number, because 81136461 - 2¹ = 81136459 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81136411) 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 in 47 ways as a sum of consecutive naturals, for example, 175771 + ... + 176231.

It is an arithmetic number, because the mean of its divisors is an integer number (2836680).

Almost surely, 2^81136461 is an apocalyptic number.

It is an amenable number.

81136461 is a deficient number, since it is larger than the sum of its proper divisors (55024179).

81136461 is a wasteful number, since it uses less digits than its factorization.

81136461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534 (or 517 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 81136461 is about 9007.5779763486. The cubic root of 81136461 is about 432.9177110914.

Adding to 81136461 its reverse (16463118), we get a palindrome (97599579).

The spelling of 81136461 in words is "eighty-one million, one hundred thirty-six thousand, four hundred sixty-one".