21388638370 has 16 divisors (see below), whose sum is σ = 41999508288. Its totient is φ = 7777686640.

The previous prime is 21388638343. The next prime is 21388638373. The reversal of 21388638370 is 7383688312.

It is not an unprimeable number, because it can be changed into a prime (21388638373) 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, 97220974 + ... + 97221193.

It is an arithmetic number, because the mean of its divisors is an integer number (2624969268).

Almost surely, 2^21388638370 is an apocalyptic number.

21388638370 is a deficient number, since it is larger than the sum of its proper divisors (20610869918).

21388638370 is a wasteful number, since it uses less digits than its factorization.

21388638370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194442185.

The product of its (nonzero) digits is 1161216, while the sum is 49.

The spelling of 21388638370 in words is "twenty-one billion, three hundred eighty-eight million, six hundred thirty-eight thousand, three hundred seventy".