21240254123 has 8 divisors (see below), whose sum is σ = 23237583600. Its totient is φ = 19253990880.

The previous prime is 21240254117. The next prime is 21240254141. The reversal of 21240254123 is 32145204212.

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

It is a cyclic number.

It is not a de Polignac number, because 21240254123 - 2¹⁸ = 21239991979 is a prime.

It is a super-2 number, since 2×21240254123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21240254092 and 21240254101.

It is not an unprimeable number, because it can be changed into a prime (21240254723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2762540 + ... + 2770217.

It is an arithmetic number, because the mean of its divisors is an integer number (2904697950).

Almost surely, 2^21240254123 is an apocalyptic number.

21240254123 is a deficient number, since it is larger than the sum of its proper divisors (1997329477).

21240254123 is a wasteful number, since it uses less digits than its factorization.

21240254123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5533117.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21240254123 its reverse (32145204212), we get a palindrome (53385458335).

The spelling of 21240254123 in words is "twenty-one billion, two hundred forty million, two hundred fifty-four thousand, one hundred twenty-three".