3920927721 has 4 divisors (see below), whose sum is σ = 5227903632. Its totient is φ = 2613951812.

The previous prime is 3920927713. The next prime is 3920927741. The reversal of 3920927721 is 1277290293.

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: 1277290293 = 3 ⋅425763431.

It is a cyclic number.

It is not a de Polignac number, because 3920927721 - 2³ = 3920927713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3920927701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 653487951 + ... + 653487956.

It is an arithmetic number, because the mean of its divisors is an integer number (1306975908).

Almost surely, 2^3920927721 is an apocalyptic number.

It is an amenable number.

3920927721 is a deficient number, since it is larger than the sum of its proper divisors (1306975911).

3920927721 is a wasteful number, since it uses less digits than its factorization.

3920927721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306975910.

The product of its (nonzero) digits is 95256, while the sum is 42.

The square root of 3920927721 is about 62617.3116717733. The cubic root of 3920927721 is about 1576.8714089776.

The spelling of 3920927721 in words is "three billion, nine hundred twenty million, nine hundred twenty-seven thousand, seven hundred twenty-one".