85811520 has 56 divisors (see below), whose sum is σ = 272454624. Its totient is φ = 22882816.

The previous prime is 85811501. The next prime is 85811521. The reversal of 85811520 is 2511858.

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 (85811521) 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, 43734 + ... + 45653.

Almost surely, 2^85811520 is an apocalyptic number.

85811520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

85811520 is an abundant number, since it is smaller than the sum of its proper divisors (186643104).

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

85811520 is a wasteful number, since it uses less digits than its factorization.

85811520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89407 (or 89397 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 30.

The square root of 85811520 is about 9263.4507609206. The cubic root of 85811520 is about 441.0777985029.

Adding to 85811520 its sum of digits (30), we get a triangular number (85811550 = T₁₃₁₀₀).

It can be divided in two parts, 8581 and 1520, that added together give a palindrome (10101).

The spelling of 85811520 in words is "eighty-five million, eight hundred eleven thousand, five hundred twenty".