81017810 has 8 divisors (see below), whose sum is σ = 145832076. Its totient is φ = 32407120.

The previous prime is 81017777. The next prime is 81017831. The reversal of 81017810 is 1871018.

It can be written as a sum of positive squares in 2 ways, for example, as 76860289 + 4157521 = 8767^2 + 2039^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81017810² = 13127771074392200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81017810.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4050881 + ... + 4050900.

Almost surely, 2^81017810 is an apocalyptic number.

81017810 is a deficient number, since it is larger than the sum of its proper divisors (64814266).

81017810 is a wasteful number, since it uses less digits than its factorization.

81017810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8101788.

The product of its (nonzero) digits is 448, while the sum is 26.

The square root of 81017810 is about 9000.9893900615. The cubic root of 81017810 is about 432.7065804533.

Adding to 81017810 its reverse (1871018), we get a palindrome (82888828).

The spelling of 81017810 in words is "eighty-one million, seventeen thousand, eight hundred ten".