3778729621 has 6 divisors (see below), whose sum is σ = 4014083330. Its totient is φ = 3556451136.

The previous prime is 3778729613. The next prime is 3778729627. The reversal of 3778729621 is 1269278773.

It can be written as a sum of positive squares in 3 ways, for example, as 1928439396 + 1850290225 = 43914^2 + 43015^2 .

It is not a de Polignac number, because 3778729621 - 2³ = 3778729613 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 (3778729627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6537306 + ... + 6537883.

Almost surely, 2^3778729621 is an apocalyptic number.

It is an amenable number.

3778729621 is a deficient number, since it is larger than the sum of its proper divisors (235353709).

3778729621 is a wasteful number, since it uses less digits than its factorization.

3778729621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13075223 (or 13075206 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 52.

The square root of 3778729621 is about 61471.3723695836. The cubic root of 3778729621 is about 1557.5737021274.

The spelling of 3778729621 in words is "three billion, seven hundred seventy-eight million, seven hundred twenty-nine thousand, six hundred twenty-one".