820115780 has 48 divisors (see below), whose sum is σ = 1922526144. Its totient is φ = 291285120.

The previous prime is 820115771. The next prime is 820115789. The reversal of 820115780 is 87511028.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (820115771) and next prime (820115789).

It is not an unprimeable number, because it can be changed into a prime (820115789) 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, 33887 + ... + 52806.

It is an arithmetic number, because the mean of its divisors is an integer number (40052628).

Almost surely, 2^820115780 is an apocalyptic number.

It is an amenable number.

820115780 is an abundant number, since it is smaller than the sum of its proper divisors (1102410364).

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

820115780 is a wasteful number, since it uses less digits than its factorization.

820115780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86756 (or 86754 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 820115780 is about 28637.6636616886. The cubic root of 820115780 is about 936.0342126560.

The spelling of 820115780 in words is "eight hundred twenty million, one hundred fifteen thousand, seven hundred eighty".