83861820 has 288 divisors, whose sum is σ = 318689280. Its totient is φ = 17418240.

The previous prime is 83861809. The next prime is 83861821. The reversal of 83861820 is 2816838.

83861820 is a `hidden beast` number, since 8 + 38 + 618 + 2 + 0 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83861821) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 742084 + ... + 742196.

It is an arithmetic number, because the mean of its divisors is an integer number (1106560).

Almost surely, 2^83861820 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 83861820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159344640).

83861820 is an abundant number, since it is smaller than the sum of its proper divisors (234827460).

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

83861820 is a wasteful number, since it uses less digits than its factorization.

83861820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 83861820 is about 9157.6099501999. The cubic root of 83861820 is about 437.7116385567.

It can be divided in two parts, 83861 and 820, that added together give a square (84681 = 291²).

The spelling of 83861820 in words is "eighty-three million, eight hundred sixty-one thousand, eight hundred twenty".