21040510123 has 16 divisors (see below), whose sum is σ = 22046902272. Its totient is φ = 20055168000.

The previous prime is 21040510103. The next prime is 21040510129. The reversal of 21040510123 is 32101504012.

It is a cyclic number.

It is not a de Polignac number, because 21040510123 - 2¹³ = 21040501931 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21040510123.

It is not an unprimeable number, because it can be changed into a prime (21040510129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2533608 + ... + 2541898.

It is an arithmetic number, because the mean of its divisors is an integer number (1377931392).

Almost surely, 2^21040510123 is an apocalyptic number.

21040510123 is a deficient number, since it is larger than the sum of its proper divisors (1006392149).

21040510123 is a wasteful number, since it uses less digits than its factorization.

21040510123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9546.

The product of its (nonzero) digits is 240, while the sum is 19.

The spelling of 21040510123 in words is "twenty-one billion, forty million, five hundred ten thousand, one hundred twenty-three".