21012105126 has 8 divisors (see below), whose sum is σ = 42024210264. Its totient is φ = 7004035040.

The previous prime is 21012105109. The next prime is 21012105137. The reversal of 21012105126 is 62150121012.

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

21012105126 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751008755 + ... + 1751008766.

It is an arithmetic number, because the mean of its divisors is an integer number (5253026283).

Almost surely, 2^21012105126 is an apocalyptic number.

21012105126 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21012105126 is a wasteful number, since it uses less digits than its factorization.

21012105126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502017526.

The product of its (nonzero) digits is 240, while the sum is 21.

Adding to 21012105126 its reverse (62150121012), we get a palindrome (83162226138).

The spelling of 21012105126 in words is "twenty-one billion, twelve million, one hundred five thousand, one hundred twenty-six".