81531350 has 24 divisors (see below), whose sum is σ = 155750448. Its totient is φ = 31730400.

The previous prime is 81531301. The next prime is 81531353. The reversal of 81531350 is 5313518.

It is a super-2 number, since 2×81531350² = 13294722065645000, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81531353) 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 11 ways as a sum of consecutive naturals, for example, 20186 + ... + 23885.

It is an arithmetic number, because the mean of its divisors is an integer number (6489602).

Almost surely, 2^81531350 is an apocalyptic number.

81531350 is a deficient number, since it is larger than the sum of its proper divisors (74219098).

81531350 is a wasteful number, since it uses less digits than its factorization.

81531350 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44120 (or 44115 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 81531350 is about 9029.4711916036. The cubic root of 81531350 is about 433.6189077495.

Adding to 81531350 its reverse (5313518), we get a palindrome (86844868).

The spelling of 81531350 in words is "eighty-one million, five hundred thirty-one thousand, three hundred fifty".