3975747807421 has 4 divisors (see below), whose sum is σ = 4281574561852. Its totient is φ = 3669921052992.

The previous prime is 3975747807379. The next prime is 3975747807433. The reversal of 3975747807421 is 1247087475793.

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 1300544091396 + 2675203716025 = 1140414^2 + 1635605^2 .

It is a cyclic number.

It is not a de Polignac number, because 3975747807421 - 2²¹ = 3975745710269 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 (3975747807121) 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, 152913377196 + ... + 152913377221.

It is an arithmetic number, because the mean of its divisors is an integer number (1070393640463).

Almost surely, 2^{3975747807421} is an apocalyptic number.

It is an amenable number.

3975747807421 is a deficient number, since it is larger than the sum of its proper divisors (305826754431).

3975747807421 is a wasteful number, since it uses less digits than its factorization.

3975747807421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305826754430.

The product of its (nonzero) digits is 82978560, while the sum is 64.

The spelling of 3975747807421 in words is "three trillion, nine hundred seventy-five billion, seven hundred forty-seven million, eight hundred seven thousand, four hundred twenty-one".