85721580 has 108 divisors (see below), whose sum is σ = 302505840. Its totient is φ = 19591488.

The previous prime is 85721569. The next prime is 85721627. The reversal of 85721580 is 8512758.

85721580 is a `hidden beast` number, since 8 + 5 + 72 + 1 + 580 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3961 + ... + 13679.

It is an arithmetic number, because the mean of its divisors is an integer number (2800980).

Almost surely, 2^85721580 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 85721580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151252920).

85721580 is an abundant number, since it is smaller than the sum of its proper divisors (216784260).

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

85721580 is a wasteful number, since it uses less digits than its factorization.

85721580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9748 (or 9736 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 85721580 is about 9258.5949257973. The cubic root of 85721580 is about 440.9236451329.

The spelling of 85721580 in words is "eighty-five million, seven hundred twenty-one thousand, five hundred eighty".