81161670 has 32 divisors (see below), whose sum is σ = 195436800. Its totient is φ = 21571040.

The previous prime is 81161669. The next prime is 81161671. The reversal of 81161670 is 7616118.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81161669) and next prime (81161671).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81161671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4981 + ... + 13679.

It is an arithmetic number, because the mean of its divisors is an integer number (6107400).

Almost surely, 2^81161670 is an apocalyptic number.

81161670 is an abundant number, since it is smaller than the sum of its proper divisors (114275130).

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

81161670 is a wasteful number, since it uses less digits than its factorization.

81161670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9020.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 81161670 is about 9008.9771894483. The cubic root of 81161670 is about 432.9625421179.

Adding to 81161670 its reverse (7616118), we get a palindrome (88777788).

It can be divided in two parts, 811 and 61670, that added together give a triangular number (62481 = T₃₅₃).

The spelling of 81161670 in words is "eighty-one million, one hundred sixty-one thousand, six hundred seventy".