21213452621 has 8 divisors (see below), whose sum is σ = 22172745600. Its totient is φ = 20257240432.

The previous prime is 21213452587. The next prime is 21213452629. The reversal of 21213452621 is 12625431212.

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

It is not a de Polignac number, because 21213452621 - 2³⁰ = 20139710797 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 (21213452629) 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, 756110 + ... + 783663.

It is an arithmetic number, because the mean of its divisors is an integer number (2771593200).

Almost surely, 2^21213452621 is an apocalyptic number.

It is an amenable number.

21213452621 is a deficient number, since it is larger than the sum of its proper divisors (959292979).

21213452621 is a wasteful number, since it uses less digits than its factorization.

21213452621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540395.

The product of its digits is 5760, while the sum is 29.

Adding to 21213452621 its reverse (12625431212), we get a palindrome (33838883833).

The spelling of 21213452621 in words is "twenty-one billion, two hundred thirteen million, four hundred fifty-two thousand, six hundred twenty-one".