21515420423344 has 40 divisors (see below), whose sum is σ = 41714924414240. Its totient is φ = 10750279938048.

The previous prime is 21515420423297. The next prime is 21515420423347. The reversal of 21515420423344 is 44332402451512.

It is a junction number, because it is equal to n+sod(n) for n = 21515420423297 and 21515420423306.

It is not an unprimeable number, because it can be changed into a prime (21515420423347) 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, 317410384 + ... + 317478160.

It is an arithmetic number, because the mean of its divisors is an integer number (1042873110356).

Almost surely, 2^{21515420423344} is an apocalyptic number.

It is an amenable number.

21515420423344 is a deficient number, since it is larger than the sum of its proper divisors (20199503990896).

21515420423344 is a wasteful number, since it uses less digits than its factorization.

21515420423344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81197 (or 81191 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 40.

Adding to 21515420423344 its reverse (44332402451512), we get a palindrome (65847822874856).

The spelling of 21515420423344 in words is "twenty-one trillion, five hundred fifteen billion, four hundred twenty million, four hundred twenty-three thousand, three hundred forty-four".