7844138037781 has 4 divisors (see below), whose sum is σ = 7873083196864. Its totient is φ = 7815192878700.

The previous prime is 7844138037767. The next prime is 7844138037797. The reversal of 7844138037781 is 1877308314487.

It is a happy number.

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 7844138037781 - 2⁷ = 7844138037653 is a prime.

It is a super-2 number, since 2×7844138037781² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7844138037731) 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, 14472579135 + ... + 14472579676.

It is an arithmetic number, because the mean of its divisors is an integer number (1968270799216).

Almost surely, 2^{7844138037781} is an apocalyptic number.

It is an amenable number.

7844138037781 is a deficient number, since it is larger than the sum of its proper divisors (28945159083).

7844138037781 is a wasteful number, since it uses less digits than its factorization.

7844138037781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28945159082.

The product of its (nonzero) digits is 25288704, while the sum is 61.

The spelling of 7844138037781 in words is "seven trillion, eight hundred forty-four billion, one hundred thirty-eight million, thirty-seven thousand, seven hundred eighty-one".