21388718452 has 24 divisors (see below), whose sum is σ = 38236052736. Its totient is φ = 10464244128.

The previous prime is 21388718447. The next prime is 21388718459. The reversal of 21388718452 is 25481788312.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21388718396 and 21388718405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388718459) 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, 915873 + ... + 938935.

It is an arithmetic number, because the mean of its divisors is an integer number (1593168864).

Almost surely, 2^21388718452 is an apocalyptic number.

It is an amenable number.

21388718452 is a deficient number, since it is larger than the sum of its proper divisors (16847334284).

21388718452 is a wasteful number, since it uses less digits than its factorization.

21388718452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28047 (or 28045 counting only the distinct ones).

The product of its digits is 860160, while the sum is 49.

The spelling of 21388718452 in words is "twenty-one billion, three hundred eighty-eight million, seven hundred eighteen thousand, four hundred fifty-two".