21621404717 has 8 divisors (see below), whose sum is σ = 23919198912. Its totient is φ = 19378979200.

The previous prime is 21621404713. The next prime is 21621404731. The reversal of 21621404717 is 71740412612.

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 21621404717 - 2² = 21621404713 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621404713) 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, 13841348 + ... + 13842909.

It is an arithmetic number, because the mean of its divisors is an integer number (2989899864).

Almost surely, 2^21621404717 is an apocalyptic number.

It is an amenable number.

21621404717 is a deficient number, since it is larger than the sum of its proper divisors (2297794195).

21621404717 is a wasteful number, since it uses less digits than its factorization.

21621404717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27684339.

The product of its (nonzero) digits is 18816, while the sum is 35.

The spelling of 21621404717 in words is "twenty-one billion, six hundred twenty-one million, four hundred four thousand, seven hundred seventeen".