79780820 has 36 divisors (see below), whose sum is σ = 194895540. Its totient is φ = 27353088.

The previous prime is 79780819. The next prime is 79780823. The reversal of 79780820 is 2808797.

79780820 = 55⁴ + 56⁴ + ... + 61⁴.

It can be written as a sum of positive squares in 2 ways, for example, as 28601104 + 51179716 = 5348^2 + 7154^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79780823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39725 + ... + 41684.

It is an arithmetic number, because the mean of its divisors is an integer number (5413765).

Almost surely, 2^79780820 is an apocalyptic number.

79780820 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

79780820 is an abundant number, since it is smaller than the sum of its proper divisors (115114720).

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

79780820 is a wasteful number, since it uses less digits than its factorization.

79780820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81432 (or 81423 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 41.

The square root of 79780820 is about 8932.0109717801. The cubic root of 79780820 is about 430.4930705915.

The spelling of 79780820 in words is "seventy-nine million, seven hundred eighty thousand, eight hundred twenty".