3993131521 has 4 divisors (see below), whose sum is σ = 3995662000. Its totient is φ = 3990601044.

The previous prime is 3993131507. The next prime is 3993131537. The reversal of 3993131521 is 1251313993.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1251313993 = 11483 ⋅108971.

It is a cyclic number.

It is not a de Polignac number, because 3993131521 - 2³¹ = 1845647873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3993131221) 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, 1262871 + ... + 1266028.

It is an arithmetic number, because the mean of its divisors is an integer number (998915500).

Almost surely, 2^3993131521 is an apocalyptic number.

It is an amenable number.

3993131521 is a deficient number, since it is larger than the sum of its proper divisors (2530479).

3993131521 is a wasteful number, since it uses less digits than its factorization.

3993131521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2530478.

The product of its digits is 21870, while the sum is 37.

The square root of 3993131521 is about 63191.2297791394. The cubic root of 3993131521 is about 1586.4919455221.

The spelling of 3993131521 in words is "three billion, nine hundred ninety-three million, one hundred thirty-one thousand, five hundred twenty-one".