21405518038 has 16 divisors (see below), whose sum is σ = 32813351424. Its totient is φ = 10468038760.

The previous prime is 21405518021. The next prime is 21405518039. The reversal of 21405518038 is 83081550412.

It is a junction number, because it is equal to n+sod(n) for n = 21405517988 and 21405518006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405518039) 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, 66681 + ... + 217387.

It is an arithmetic number, because the mean of its divisors is an integer number (2050834464).

Almost surely, 2^21405518038 is an apocalyptic number.

21405518038 is a deficient number, since it is larger than the sum of its proper divisors (11407833386).

21405518038 is a wasteful number, since it uses less digits than its factorization.

21405518038 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152267.

The product of its (nonzero) digits is 38400, while the sum is 37.

The spelling of 21405518038 in words is "twenty-one billion, four hundred five million, five hundred eighteen thousand, thirty-eight".