82021440 has 56 divisors (see below), whose sum is σ = 260421120. Its totient is φ = 21872128.

The previous prime is 82021409. The next prime is 82021441. The reversal of 82021440 is 4412028.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82021441) 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, 41760 + ... + 43679.

Almost surely, 2^82021440 is an apocalyptic number.

82021440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

82021440 is an abundant number, since it is smaller than the sum of its proper divisors (178399680).

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

82021440 is a wasteful number, since it uses less digits than its factorization.

82021440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85459 (or 85449 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 82021440 is about 9056.5688867253. The cubic root of 82021440 is about 434.4860093761.

Adding to 82021440 its reverse (4412028), we get a palindrome (86433468).

The spelling of 82021440 in words is "eighty-two million, twenty-one thousand, four hundred forty".