4001555540 has 24 divisors (see below), whose sum is σ = 8897577192. Its totient is φ = 1506467840.

The previous prime is 4001555539. The next prime is 4001555543. The reversal of 4001555540 is 455551004.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1700242756 + 2301312784 = 41234^2 + 47972^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4001555543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5884301 + ... + 5884980.

It is an arithmetic number, because the mean of its divisors is an integer number (370732383).

Almost surely, 2^4001555540 is an apocalyptic number.

It is an amenable number.

4001555540 is an abundant number, since it is smaller than the sum of its proper divisors (4896021652).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

4001555540 is a wasteful number, since it uses less digits than its factorization.

4001555540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11769307 (or 11769305 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 29.

The square root of 4001555540 is about 63257.8496314884. The cubic root of 4001555540 is about 1587.6067974528.

The spelling of 4001555540 in words is "four billion, one million, five hundred fifty-five thousand, five hundred forty".