21440415516 has 72 divisors (see below), whose sum is σ = 54207820800. Its totient is φ = 6592682304.

The previous prime is 21440415511. The next prime is 21440415523. The reversal of 21440415516 is 61551404412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440415511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4465285 + ... + 4470083.

It is an arithmetic number, because the mean of its divisors is an integer number (752886400).

Almost surely, 2^21440415516 is an apocalyptic number.

21440415516 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21440415516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27103910400).

21440415516 is an abundant number, since it is smaller than the sum of its proper divisors (32767405284).

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

21440415516 is a wasteful number, since it uses less digits than its factorization.

21440415516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7035 (or 7020 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 33.

Adding to 21440415516 its reverse (61551404412), we get a palindrome (82991819928).

The spelling of 21440415516 in words is "twenty-one billion, four hundred forty million, four hundred fifteen thousand, five hundred sixteen".