21012023123 has 32 divisors (see below), whose sum is σ = 26035322880. Its totient is φ = 16513217280.

The previous prime is 21012023119. The next prime is 21012023141. The reversal of 21012023123 is 32132021012.

It is not a de Polignac number, because 21012023123 - 2² = 21012023119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21012020123) 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, 9383438 + ... + 9385676.

It is an arithmetic number, because the mean of its divisors is an integer number (813603840).

Almost surely, 2^21012023123 is an apocalyptic number.

21012023123 is a deficient number, since it is larger than the sum of its proper divisors (5023299757).

21012023123 is a wasteful number, since it uses less digits than its factorization.

21012023123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2907.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21012023123 its reverse (32132021012), we get a palindrome (53144044135).

The spelling of 21012023123 in words is "twenty-one billion, twelve million, twenty-three thousand, one hundred twenty-three".