8501778839961 has 81 divisors (see below), whose sum is σ = 13612388113597. Its totient is φ = 5109381361920.

The previous prime is 8501778839959. The next prime is 8501778839969. The reversal of 8501778839961 is 1699388771058.

The square root of 8501778839961 is 2915781.

It is a perfect power (a square), and thus also a powerful number.

8501778839961 is a `hidden beast` number, since 8 + 5 + 0 + 177 + 8 + 8 + 399 + 61 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 841925529225 + 7659853310736 = 917565^2 + 2767644^2 .

It is not a de Polignac number, because 8501778839961 - 2¹ = 8501778839959 is a prime.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8501778839961.

It is not an unprimeable number, because it can be changed into a prime (8501778839969) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 14336894881 + ... + 14336895473.

Almost surely, 2^{8501778839961} is an apocalyptic number.

8501778839961 is the 2915781-st square number.

8501778839961 is the 1457891-st centered octagonal number.

It is an amenable number.

8501778839961 is a deficient number, since it is larger than the sum of its proper divisors (5110609273636).

8501778839961 is an equidigital number, since it uses as much as digits as its factorization.

8501778839961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1512 (or 756 counting only the distinct ones).

The product of its (nonzero) digits is 182891520, while the sum is 72.

The spelling of 8501778839961 in words is "eight trillion, five hundred one billion, seven hundred seventy-eight million, eight hundred thirty-nine thousand, nine hundred sixty-one".