3821005921 has 4 divisors (see below), whose sum is σ = 3822336000. Its totient is φ = 3819675844.

The previous prime is 3821005919. The next prime is 3821005943. The reversal of 3821005921 is 1295001283.

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: 1295001283 = 17431 ⋅74293.

It is a cyclic number.

It is not a de Polignac number, because 3821005921 - 2¹ = 3821005919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3821002921) 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, 660721 + ... + 666478.

It is an arithmetic number, because the mean of its divisors is an integer number (955584000).

Almost surely, 2^3821005921 is an apocalyptic number.

It is an amenable number.

3821005921 is a deficient number, since it is larger than the sum of its proper divisors (1330079).

3821005921 is a wasteful number, since it uses less digits than its factorization.

3821005921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1330078.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 3821005921 is about 61814.2857355806. The cubic root of 3821005921 is about 1563.3608673608.

The spelling of 3821005921 in words is "three billion, eight hundred twenty-one million, five thousand, nine hundred twenty-one".