21018384252 has 24 divisors (see below), whose sum is σ = 54492107600. Its totient is φ = 7006128048.

The previous prime is 21018384241. The next prime is 21018384253. The reversal of 21018384252 is 25248381012.

It is a happy number.

21018384252 is a `hidden beast` number, since 2 + 10 + 18 + 384 + 252 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018384253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97307227 + ... + 97307442.

Almost surely, 2^21018384252 is an apocalyptic number.

It is an amenable number.

21018384252 is an abundant number, since it is smaller than the sum of its proper divisors (33473723348).

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

21018384252 is a wasteful number, since it uses less digits than its factorization.

21018384252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194614682 (or 194614674 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The spelling of 21018384252 in words is "twenty-one billion, eighteen million, three hundred eighty-four thousand, two hundred fifty-two".