81304570 has 16 divisors (see below), whose sum is σ = 146853000. Its totient is φ = 32409664.

The previous prime is 81304547. The next prime is 81304571. The reversal of 81304570 is 7540318.

It can be written as a sum of positive squares in 4 ways, for example, as 73736569 + 7568001 = 8587^2 + 2751^2 .

It is a super-2 number, since 2×81304570² = 13220866205769800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81304571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10945 + ... + 16804.

Almost surely, 2^81304570 is an apocalyptic number.

81304570 is a deficient number, since it is larger than the sum of its proper divisors (65548430).

81304570 is a wasteful number, since it uses less digits than its factorization.

81304570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28049.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 81304570 is about 9016.9046795450. The cubic root of 81304570 is about 433.2164964430.

Adding to 81304570 its reverse (7540318), we get a palindrome (88844888).

The spelling of 81304570 in words is "eighty-one million, three hundred four thousand, five hundred seventy".