81302570 has 16 divisors (see below), whose sum is σ = 146641320. Its totient is φ = 32455104.

The previous prime is 81302521. The next prime is 81302581. The reversal of 81302570 is 7520318.

It can be written as a sum of positive squares in 4 ways, for example, as 79085449 + 2217121 = 8893^2 + 1489^2 .

It is a super-2 number, since 2×81302570² = 13220215777209800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2897 + ... + 13076.

Almost surely, 2^81302570 is an apocalyptic number.

81302570 is a deficient number, since it is larger than the sum of its proper divisors (65338750).

81302570 is a wasteful number, since it uses less digits than its factorization.

81302570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16489.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 81302570 is about 9016.7937760603. The cubic root of 81302570 is about 433.2129442027.

Adding to 81302570 its reverse (7520318), we get a palindrome (88822888).

The spelling of 81302570 in words is "eighty-one million, three hundred two thousand, five hundred seventy".