81370170 has 160 divisors (see below), whose sum is σ = 254251008. Its totient is φ = 18289152.

The previous prime is 81370169. The next prime is 81370213. The reversal of 81370170 is 7107318.

It is a super-2 number, since 2×81370170² = 13242209131657800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 640647 + ... + 640773.

Almost surely, 2^81370170 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81370170, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127125504).

81370170 is an abundant number, since it is smaller than the sum of its proper divisors (172880838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81370170 is a wasteful number, since it uses less digits than its factorization.

81370170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

The square root of 81370170 is about 9020.5415580219. The cubic root of 81370170 is about 433.3329776460.

Adding to 81370170 its reverse (7107318), we get a palindrome (88477488).

The spelling of 81370170 in words is "eighty-one million, three hundred seventy thousand, one hundred seventy".