388500021 has 24 divisors (see below), whose sum is σ = 690668160. Its totient is φ = 204922656.

The previous prime is 388499999. The next prime is 388500023. The reversal of 388500021 is 120005883.

It is a happy number.

388500021 is nontrivially palindromic in base 4.

It is not a de Polignac number, because 388500021 - 2⁷ = 388499893 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (388500023) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 236361 + ... + 237998.

It is an arithmetic number, because the mean of its divisors is an integer number (28777840).

Almost surely, 2^388500021 is an apocalyptic number.

It is an amenable number.

388500021 is a deficient number, since it is larger than the sum of its proper divisors (302168139).

388500021 is a wasteful number, since it uses less digits than its factorization.

388500021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474385 (or 474382 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 388500021 is about 19710.4038771406. The cubic root of 388500021 is about 729.6764820291.

The spelling of 388500021 in words is "three hundred eighty-eight million, five hundred thousand, twenty-one".