21318212526 has 64 divisors (see below), whose sum is σ = 46256132160. Its totient is φ = 6511011840.

The previous prime is 21318212491. The next prime is 21318212563. The reversal of 21318212526 is 62521281312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14316390 + ... + 14317878.

It is an arithmetic number, because the mean of its divisors is an integer number (722752065).

Almost surely, 2^21318212526 is an apocalyptic number.

21318212526 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21318212526 is an abundant number, since it is smaller than the sum of its proper divisors (24937919634).

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

21318212526 is a wasteful number, since it uses less digits than its factorization.

21318212526 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2741.

The product of its digits is 11520, while the sum is 33.

Adding to 21318212526 its reverse (62521281312), we get a palindrome (83839493838).

The spelling of 21318212526 in words is "twenty-one billion, three hundred eighteen million, two hundred twelve thousand, five hundred twenty-six".