2781868261 has 4 divisors (see below), whose sum is σ = 2928282400. Its totient is φ = 2635454124.

The previous prime is 2781868259. The next prime is 2781868267. The reversal of 2781868261 is 1628681872.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2781868261 - 2¹ = 2781868259 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 (2781868267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73207041 + ... + 73207078.

It is an arithmetic number, because the mean of its divisors is an integer number (732070600).

Almost surely, 2^2781868261 is an apocalyptic number.

It is an amenable number.

2781868261 is a deficient number, since it is larger than the sum of its proper divisors (146414139).

2781868261 is a wasteful number, since it uses less digits than its factorization.

2781868261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146414138.

The product of its digits is 516096, while the sum is 49.

The square root of 2781868261 is about 52743.4191250435. The cubic root of 2781868261 is about 1406.4107798497.

The spelling of 2781868261 in words is "two billion, seven hundred eighty-one million, eight hundred sixty-eight thousand, two hundred sixty-one".