3721939021 has 4 divisors (see below), whose sum is σ = 3736421532. Its totient is φ = 3707456512.

The previous prime is 3721939007. The next prime is 3721939049. The reversal of 3721939021 is 1209391273.

It is a happy number.

3721939021 is digitally balanced in base 2, 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 an emirpimes, since its reverse is a distinct semiprime: 1209391273 = 173 ⋅6990701.

It can be written as a sum of positive squares in 2 ways, for example, as 3360520900 + 361418121 = 57970^2 + 19011^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3721939021 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 (3721909021) 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, 7240870 + ... + 7241383.

It is an arithmetic number, because the mean of its divisors is an integer number (934105383).

Almost surely, 2^3721939021 is an apocalyptic number.

It is an amenable number.

3721939021 is a deficient number, since it is larger than the sum of its proper divisors (14482511).

3721939021 is a wasteful number, since it uses less digits than its factorization.

3721939021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14482510.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 3721939021 is about 61007.6964079123. The cubic root of 3721939021 is about 1549.7313472645.

The spelling of 3721939021 in words is "three billion, seven hundred twenty-one million, nine hundred thirty-nine thousand, twenty-one".