81353140 has 36 divisors (see below), whose sum is σ = 187790148. Its totient is φ = 29582080.

The previous prime is 81353123. The next prime is 81353141. The reversal of 81353140 is 4135318.

It can be written as a sum of positive squares in 2 ways, for example, as 18974736 + 62378404 = 4356^2 + 7898^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81353141) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14389 + ... + 19228.

It is an arithmetic number, because the mean of its divisors is an integer number (5216393).

Almost surely, 2^81353140 is an apocalyptic number.

It is an amenable number.

81353140 is an abundant number, since it is smaller than the sum of its proper divisors (106437008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81353140 is a wasteful number, since it uses less digits than its factorization.

81353140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33648 (or 33635 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 81353140 is about 9019.5975519975. The cubic root of 81353140 is about 433.3027447179.

Adding to 81353140 its reverse (4135318), we get a palindrome (85488458).

The spelling of 81353140 in words is "eighty-one million, three hundred fifty-three thousand, one hundred forty".