21123000030 has 64 divisors (see below), whose sum is σ = 55431952128. Its totient is φ = 5108866560.

The previous prime is 21123000011. The next prime is 21123000047. The reversal of 21123000030 is 3000032112.

It is a happy number.

It is a super-2 number, since 2×21123000030² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 68977 + ... + 216803.

It is an arithmetic number, because the mean of its divisors is an integer number (866124252).

Almost surely, 2^21123000030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123000030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27715976064).

21123000030 is an abundant number, since it is smaller than the sum of its proper divisors (34308952098).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21123000030 is a wasteful number, since it uses less digits than its factorization.

21123000030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148281.

The product of its (nonzero) digits is 36, while the sum is 12.

Adding to 21123000030 its reverse (3000032112), we get a palindrome (24123032142).

The spelling of 21123000030 in words is "twenty-one billion, one hundred twenty-three million, thirty", and thus it is an aban number.