21123380621 has 8 divisors (see below), whose sum is σ = 24141943680. Its totient is φ = 18105051888.

The previous prime is 21123380611. The next prime is 21123380653. The reversal of 21123380621 is 12608332112.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-21123380621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123380611) 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, 228200 + ... + 307118.

It is an arithmetic number, because the mean of its divisors is an integer number (3017742960).

Almost surely, 2^21123380621 is an apocalyptic number.

It is an amenable number.

21123380621 is a deficient number, since it is larger than the sum of its proper divisors (3018563059).

21123380621 is an equidigital number, since it uses as much as digits as its factorization.

21123380621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117163.

The product of its (nonzero) digits is 3456, while the sum is 29.

The spelling of 21123380621 in words is "twenty-one billion, one hundred twenty-three million, three hundred eighty thousand, six hundred twenty-one".