82720813 has 16 divisors (see below), whose sum is σ = 101009920. Its totient is φ = 66162096.

The previous prime is 82720747. The next prime is 82720817. The reversal of 82720813 is 31802728.

It is a de Polignac number, because none of the positive numbers 2^k-82720813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82720817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4270 + ... + 13552.

It is an arithmetic number, because the mean of its divisors is an integer number (6313120).

Almost surely, 2^82720813 is an apocalyptic number.

It is an amenable number.

82720813 is a deficient number, since it is larger than the sum of its proper divisors (18289107).

82720813 is a wasteful number, since it uses less digits than its factorization.

82720813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9376.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 82720813 is about 9095.0982952357. The cubic root of 82720813 is about 435.7174280062.

The spelling of 82720813 in words is "eighty-two million, seven hundred twenty thousand, eight hundred thirteen".