21001011011123 has 32 divisors (see below), whose sum is σ = 25524077745600. Its totient is φ = 17015005324800.

The previous prime is 21001011011117. The next prime is 21001011011153. The reversal of 21001011011123 is 32111011010012.

It is a cyclic number.

It is not a de Polignac number, because 21001011011123 - 2⁶ = 21001011011059 is a prime.

It is a super-2 number, since 2×21001011011123² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001011011098 and 21001011011107.

It is not an unprimeable number, because it can be changed into a prime (21001011011153) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 191789633 + ... + 191899101.

It is an arithmetic number, because the mean of its divisors is an integer number (797627429550).

Almost surely, 2^{21001011011123} is an apocalyptic number.

21001011011123 is a deficient number, since it is larger than the sum of its proper divisors (4523066734477).

21001011011123 is a wasteful number, since it uses less digits than its factorization.

21001011011123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155783.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 21001011011123 its reverse (32111011010012), we get a palindrome (53112022021135).

The spelling of 21001011011123 in words is "twenty-one trillion, one billion, eleven million, eleven thousand, one hundred twenty-three".