21216360021 has 8 divisors (see below), whose sum is σ = 28293148704. Its totient is φ = 14141905680.

The previous prime is 21216359993. The next prime is 21216360047. The reversal of 21216360021 is 12006361212.

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

It is not a de Polignac number, because 21216360021 - 2⁹ = 21216359509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21216359973 and 21216360000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216360421) 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, 562266 + ... + 598811.

It is an arithmetic number, because the mean of its divisors is an integer number (3536643588).

Almost surely, 2^21216360021 is an apocalyptic number.

It is an amenable number.

21216360021 is a deficient number, since it is larger than the sum of its proper divisors (7076788683).

21216360021 is a wasteful number, since it uses less digits than its factorization.

21216360021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167171.

The product of its (nonzero) digits is 864, while the sum is 24.

The spelling of 21216360021 in words is "twenty-one billion, two hundred sixteen million, three hundred sixty thousand, twenty-one".