21621016115615 has 8 divisors (see below), whose sum is σ = 29651679244320. Its totient is φ = 14825839622112.

The previous prime is 21621016115509. The next prime is 21621016115627. The reversal of 21621016115615 is 51651161012612.

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

It is a cyclic number.

It is not a de Polignac number, because 21621016115615 - 2⁸ = 21621016115359 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 308871658760 + ... + 308871658829.

It is an arithmetic number, because the mean of its divisors is an integer number (3706459905540).

Almost surely, 2^{21621016115615} is an apocalyptic number.

21621016115615 is a deficient number, since it is larger than the sum of its proper divisors (8030663128705).

21621016115615 is an equidigital number, since it uses as much as digits as its factorization.

21621016115615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617743317601.

The product of its (nonzero) digits is 21600, while the sum is 38.

The spelling of 21621016115615 in words is "twenty-one trillion, six hundred twenty-one billion, sixteen million, one hundred fifteen thousand, six hundred fifteen".