3992849721 has 135 divisors (see below), whose sum is σ = 7497639039. Its totient is φ = 2111018112.

The previous prime is 3992849719. The next prime is 3992849761. The reversal of 3992849721 is 1279482993.

The square root of 3992849721 is 63189.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3108620025 + 884229696 = 55755^2 + 29736^2 .

It is not a de Polignac number, because 3992849721 - 2¹ = 3992849719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3992849761) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 67675390 + ... + 67675448.

Almost surely, 2^3992849721 is an apocalyptic number.

3992849721 is the 63189-th square number.

3992849721 is the 31595-th centered octagonal number.

It is an amenable number.

3992849721 is a deficient number, since it is larger than the sum of its proper divisors (3504789318).

3992849721 is an equidigital number, since it uses as much as digits as its factorization.

3992849721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178 (or 86 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The cubic root of 3992849721 is about 1586.4546244417.

The spelling of 3992849721 in words is "three billion, nine hundred ninety-two million, eight hundred forty-nine thousand, seven hundred twenty-one".