2609983781 has 8 divisors (see below), whose sum is σ = 2724090264. Its totient is φ = 2498279680.

The previous prime is 2609983777. The next prime is 2609983793. The reversal of 2609983781 is 1873899062.

It can be written as a sum of positive squares in 4 ways, for example, as 650505025 + 1959478756 = 25505^2 + 44266^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2609983781 - 2² = 2609983777 is a prime.

It is a super-3 number, since 3×2609983781³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2609983741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 598376 + ... + 602721.

It is an arithmetic number, because the mean of its divisors is an integer number (340511283).

Almost surely, 2^2609983781 is an apocalyptic number.

It is an amenable number.

2609983781 is a deficient number, since it is larger than the sum of its proper divisors (114106483).

2609983781 is a wasteful number, since it uses less digits than its factorization.

2609983781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201191.

The product of its (nonzero) digits is 1306368, while the sum is 53.

The square root of 2609983781 is about 51088.0003621203. Note that the first 3 decimals coincide. The cubic root of 2609983781 is about 1376.8266685959.

The spelling of 2609983781 in words is "two billion, six hundred nine million, nine hundred eighty-three thousand, seven hundred eighty-one".