81671652 has 60 divisors (see below), whose sum is σ = 224759920. Its totient is φ = 25789104.

The previous prime is 81671599. The next prime is 81671657. The reversal of 81671652 is 25617618.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81671657) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 478 + ... + 12789.

Almost surely, 2^81671652 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81671652, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112379960).

81671652 is an abundant number, since it is smaller than the sum of its proper divisors (143088268).

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

81671652 is a wasteful number, since it uses less digits than its factorization.

81671652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13302 (or 13291 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 81671652 is about 9037.2369671266. The cubic root of 81671652 is about 433.8674940751.

The spelling of 81671652 in words is "eighty-one million, six hundred seventy-one thousand, six hundred fifty-two".