82131840 has 384 divisors, whose sum is σ = 341863200. Its totient is φ = 18579456.

The previous prime is 82131839. The next prime is 82131853. The reversal of 82131840 is 4813128.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 846672 + ... + 846768.

Almost surely, 2^82131840 is an apocalyptic number.

82131840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 82131840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170931600).

82131840 is an abundant number, since it is smaller than the sum of its proper divisors (259731360).

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

82131840 is a wasteful number, since it uses less digits than its factorization.

82131840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 82131840 is about 9062.6618606235. The cubic root of 82131840 is about 434.6808598541.

Adding to 82131840 its reverse (4813128), we get a palindrome (86944968).

The spelling of 82131840 in words is "eighty-two million, one hundred thirty-one thousand, eight hundred forty".