2788981621 has 4 divisors (see below), whose sum is σ = 2789940652. Its totient is φ = 2788022592.

The previous prime is 2788981607. The next prime is 2788981669. The reversal of 2788981621 is 1261898872.

It is a happy number.

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 1928439396 + 860542225 = 43914^2 + 29335^2 .

It is a cyclic number.

It is not a de Polignac number, because 2788981621 - 2⁹ = 2788981109 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 (2788981691) 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, 475140 + ... + 480973.

It is an arithmetic number, because the mean of its divisors is an integer number (697485163).

Almost surely, 2^2788981621 is an apocalyptic number.

It is an amenable number.

2788981621 is a deficient number, since it is larger than the sum of its proper divisors (959031).

2788981621 is an equidigital number, since it uses as much as digits as its factorization.

2788981621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 959030.

The product of its digits is 774144, while the sum is 52.

The square root of 2788981621 is about 52810.8096983941. The cubic root of 2788981621 is about 1407.6085110372.

The spelling of 2788981621 in words is "two billion, seven hundred eighty-eight million, nine hundred eighty-one thousand, six hundred twenty-one".