21621542434266 has 8 divisors (see below), whose sum is σ = 43243084868544. Its totient is φ = 7207180811420.

The previous prime is 21621542434231. The next prime is 21621542434313. The reversal of 21621542434266 is 66243424512612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21621542434266 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1801795202850 + ... + 1801795202861.

It is an arithmetic number, because the mean of its divisors is an integer number (5405385608568).

Almost surely, 2^{21621542434266} is an apocalyptic number.

21621542434266 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21621542434266 is a wasteful number, since it uses less digits than its factorization.

21621542434266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3603590405716.

The product of its digits is 3317760, while the sum is 48.

Adding to 21621542434266 its reverse (66243424512612), we get a palindrome (87864966946878).

The spelling of 21621542434266 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred forty-two million, four hundred thirty-four thousand, two hundred sixty-six".