3977998421 has 4 divisors (see below), whose sum is σ = 4019008812. Its totient is φ = 3936988032.

The previous prime is 3977998397. The next prime is 3977998439. The reversal of 3977998421 is 1248997793.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2032747396 + 1945251025 = 45086^2 + 44105^2 .

It is a cyclic number.

It is not a de Polignac number, because 3977998421 - 2⁶ = 3977998357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3977998481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20505050 + ... + 20505243.

It is an arithmetic number, because the mean of its divisors is an integer number (1004752203).

Almost surely, 2^3977998421 is an apocalyptic number.

It is an amenable number.

3977998421 is a deficient number, since it is larger than the sum of its proper divisors (41010391).

3977998421 is an equidigital number, since it uses as much as digits as its factorization.

3977998421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41010390.

The product of its digits is 6858432, while the sum is 59.

The square root of 3977998421 is about 63071.3756073229. The cubic root of 3977998421 is about 1584.4852552673.

The spelling of 3977998421 in words is "three billion, nine hundred seventy-seven million, nine hundred ninety-eight thousand, four hundred twenty-one".