2784742721 has 4 divisors (see below), whose sum is σ = 2784989892. Its totient is φ = 2784495552.

The previous prime is 2784742717. The next prime is 2784742757. The reversal of 2784742721 is 1272474872.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2404921600 + 379821121 = 49040^2 + 19489^2 .

It is a cyclic number.

It is not a de Polignac number, because 2784742721 - 2² = 2784742717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2784702721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105836 + ... + 129501.

It is an arithmetic number, because the mean of its divisors is an integer number (696247473).

Almost surely, 2^2784742721 is an apocalyptic number.

It is an amenable number.

2784742721 is a deficient number, since it is larger than the sum of its proper divisors (247171).

2784742721 is a wasteful number, since it uses less digits than its factorization.

2784742721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247170.

The product of its digits is 351232, while the sum is 44.

The square root of 2784742721 is about 52770.6615554514. The cubic root of 2784742721 is about 1406.8950203601.

The spelling of 2784742721 in words is "two billion, seven hundred eighty-four million, seven hundred forty-two thousand, seven hundred twenty-one".