4000978821 has 12 divisors (see below), whose sum is σ = 6205600032. Its totient is φ = 2286273528.

The previous prime is 4000978801. The next prime is 4000978847. The reversal of 4000978821 is 1288790004.

It is not a de Polignac number, because 4000978821 - 2¹⁷ = 4000847749 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 4000978821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4000978801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13608625 + ... + 13608918.

It is an arithmetic number, because the mean of its divisors is an integer number (517133336).

Almost surely, 2^4000978821 is an apocalyptic number.

It is an amenable number.

4000978821 is a deficient number, since it is larger than the sum of its proper divisors (2204621211).

4000978821 is a wasteful number, since it uses less digits than its factorization.

4000978821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27217560 (or 27217553 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 4000978821 is about 63253.2909894813. The cubic root of 4000978821 is about 1587.5305231984.

The spelling of 4000978821 in words is "four billion, nine hundred seventy-eight thousand, eight hundred twenty-one".