21541619123 has 2 divisors, whose sum is σ = 21541619124. Its totient is φ = 21541619122.

The previous prime is 21541619107. The next prime is 21541619153. The reversal of 21541619123 is 32191614512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21541619123 - 2⁴ = 21541619107 is a prime.

It is not a weakly prime, because it can be changed into another prime (21541619153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770809561 + 10770809562.

It is an arithmetic number, because the mean of its divisors is an integer number (10770809562).

Almost surely, 2^21541619123 is an apocalyptic number.

21541619123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541619123 is an equidigital number, since it uses as much as digits as its factorization.

21541619123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 35.

The spelling of 21541619123 in words is "twenty-one billion, five hundred forty-one million, six hundred nineteen thousand, one hundred twenty-three".