3945551746781 has 4 divisors (see below), whose sum is σ = 4037308764192. Its totient is φ = 3853794729372.

The previous prime is 3945551746771. The next prime is 3945551746841. The reversal of 3945551746781 is 1876471555493.

It is a happy number.

3945551746781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 3945551746781 - 2¹⁴ = 3945551730397 is a prime.

It is a super-2 number, since 2×3945551746781² (a number of 26 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 (3945551746771) 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, 45878508641 + ... + 45878508726.

It is an arithmetic number, because the mean of its divisors is an integer number (1009327191048).

Almost surely, 2^{3945551746781} is an apocalyptic number.

It is an amenable number.

3945551746781 is a deficient number, since it is larger than the sum of its proper divisors (91757017411).

3945551746781 is an equidigital number, since it uses as much as digits as its factorization.

3945551746781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91757017410.

The product of its digits is 127008000, while the sum is 65.

The spelling of 3945551746781 in words is "three trillion, nine hundred forty-five billion, five hundred fifty-one million, seven hundred forty-six thousand, seven hundred eighty-one".