81505430 has 32 divisors (see below), whose sum is σ = 149022720. Its totient is φ = 32093280.

The previous prime is 81505427. The next prime is 81505439. The reversal of 81505430 is 3450518.

It is a self number, because there is not a number n which added to its sum of digits gives 81505430.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81505439) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 265337 + ... + 265643.

It is an arithmetic number, because the mean of its divisors is an integer number (4656960).

Almost surely, 2^81505430 is an apocalyptic number.

81505430 is a deficient number, since it is larger than the sum of its proper divisors (67517290).

81505430 is a wasteful number, since it uses less digits than its factorization.

81505430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 81505430 is about 9028.0357775100. The cubic root of 81505430 is about 433.5729516301.

Adding to 81505430 its reverse (3450518), we get a palindrome (84955948).

The spelling of 81505430 in words is "eighty-one million, five hundred five thousand, four hundred thirty".