2781493463961 has 15 divisors (see below), whose sum is σ = 4155092905711. Its totient is φ = 1854318969288.

The previous prime is 2781493463939. The next prime is 2781493463971. The reversal of 2781493463961 is 1693643941872.

The square root of 2781493463961 is 1667781.

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

2781493463961 is a `hidden beast` number, since 2 + 7 + 81 + 4 + 9 + 3 + 463 + 96 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2364616628361 + 416876835600 = 1537731^2 + 645660^2 .

It is not a de Polignac number, because 2781493463961 - 2⁵ = 2781493463929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2781493463971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 14917375 + ... + 15102683.

Almost surely, 2^{2781493463961} is an apocalyptic number.

2781493463961 is the 1667781-st square number.

2781493463961 is the 833891-st centered octagonal number.

It is an amenable number.

2781493463961 is a deficient number, since it is larger than the sum of its proper divisors (1373599441750).

2781493463961 is an frugal number, since it uses more digits than its factorization.

2781493463961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370630 (or 185312 counting only the distinct ones).

The product of its digits is 47029248, while the sum is 63.

The spelling of 2781493463961 in words is "two trillion, seven hundred eighty-one billion, four hundred ninety-three million, four hundred sixty-three thousand, nine hundred sixty-one".