81210530 has 32 divisors (see below), whose sum is σ = 155229696. Its totient is φ = 30484224.

The previous prime is 81210511. The next prime is 81210587. The reversal of 81210530 is 3501218.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 102797 + ... + 103583.

It is an arithmetic number, because the mean of its divisors is an integer number (4850928).

Almost surely, 2^81210530 is an apocalyptic number.

81210530 is a deficient number, since it is larger than the sum of its proper divisors (74019166).

81210530 is a wasteful number, since it uses less digits than its factorization.

81210530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1418.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 81210530 is about 9011.6885210265. The cubic root of 81210530 is about 433.0494070389.

Adding to 81210530 its reverse (3501218), we get a palindrome (84711748).

The spelling of 81210530 in words is "eighty-one million, two hundred ten thousand, five hundred thirty".