3945792729221 has 12 divisors (see below), whose sum is σ = 4748279781420. Its totient is φ = 3265483636800.

The previous prime is 3945792729181. The next prime is 3945792729251. The reversal of 3945792729221 is 1229272975493.

3945792729221 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 2491706448196 + 1454086281025 = 1578514^2 + 1205855^2 .

It is not a de Polignac number, because 3945792729221 - 2¹⁸ = 3945792467077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3945792729251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1388384480 + ... + 1388387321.

It is an arithmetic number, because the mean of its divisors is an integer number (395689981785).

Almost surely, 2^{3945792729221} is an apocalyptic number.

It is an amenable number.

3945792729221 is a deficient number, since it is larger than the sum of its proper divisors (802487052199).

3945792729221 is a wasteful number, since it uses less digits than its factorization.

3945792729221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2776771844 (or 2776771837 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 62.

The spelling of 3945792729221 in words is "three trillion, nine hundred forty-five billion, seven hundred ninety-two million, seven hundred twenty-nine thousand, two hundred twenty-one".