82721520 has 160 divisors (see below), whose sum is σ = 325693440. Its totient is φ = 18904320.

The previous prime is 82721491. The next prime is 82721521. The reversal of 82721520 is 2512728.

It is a super-2 number, since 2×82721520² = 13685699742220800, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82721521) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12385 + ... + 17855.

It is an arithmetic number, because the mean of its divisors is an integer number (2035584).

Almost surely, 2^82721520 is an apocalyptic number.

82721520 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 82721520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162846720).

82721520 is an abundant number, since it is smaller than the sum of its proper divisors (242971920).

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

82721520 is a wasteful number, since it uses less digits than its factorization.

82721520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5500 (or 5488 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 82721520 is about 9095.1371622422. The cubic root of 82721520 is about 435.7186693356.

The spelling of 82721520 in words is "eighty-two million, seven hundred twenty-one thousand, five hundred twenty".