82779840 has 448 divisors, whose sum is σ = 348203520. Its totient is φ = 18247680.

The previous prime is 82779839. The next prime is 82779847. The reversal of 82779840 is 4897728.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82779847) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1235487 + ... + 1235553.

It is an arithmetic number, because the mean of its divisors is an integer number (777240).

Almost surely, 2^82779840 is an apocalyptic number.

82779840 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 82779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174101760).

82779840 is an abundant number, since it is smaller than the sum of its proper divisors (265423680).

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

82779840 is a wasteful number, since it uses less digits than its factorization.

82779840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The square root of 82779840 is about 9098.3427062295. The cubic root of 82779840 is about 435.8210415010.

The spelling of 82779840 in words is "eighty-two million, seven hundred seventy-nine thousand, eight hundred forty".