81317810 has 16 divisors (see below), whose sum is σ = 167282496. Its totient is φ = 27880368.

The previous prime is 81317807. The next prime is 81317813. The reversal of 81317810 is 1871318.

It is an interprime number because it is at equal distance from previous prime (81317807) and next prime (81317813).

It is a super-2 number, since 2×81317810² = 13225172446392200, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81317813) 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, 580772 + ... + 580911.

It is an arithmetic number, because the mean of its divisors is an integer number (10455156).

Almost surely, 2^81317810 is an apocalyptic number.

81317810 is an abundant number, since it is smaller than the sum of its proper divisors (85964686).

81317810 is a wasteful number, since it uses less digits than its factorization.

81317810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1161697.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 81317810 is about 9017.6388262117. The cubic root of 81317810 is about 433.2400108043.

The spelling of 81317810 in words is "eighty-one million, three hundred seventeen thousand, eight hundred ten".