21123423224521 has 8 divisors (see below), whose sum is σ = 21178192875840. Its totient is φ = 21068655972912.

The previous prime is 21123423224509. The next prime is 21123423224551. The reversal of 21123423224521 is 12542232432112.

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 21123423224521 - 2⁹ = 21123423224009 is a prime.

It is a super-2 number, since 2×21123423224521² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123423224551) 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, 17754676 + ... + 18907018.

It is an arithmetic number, because the mean of its divisors is an integer number (2647274109480).

Almost surely, 2^{21123423224521} is an apocalyptic number.

It is an amenable number.

21123423224521 is a deficient number, since it is larger than the sum of its proper divisors (54769651319).

21123423224521 is a wasteful number, since it uses less digits than its factorization.

21123423224521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1199855.

The product of its digits is 46080, while the sum is 34.

Adding to 21123423224521 its reverse (12542232432112), we get a palindrome (33665655656633).

The spelling of 21123423224521 in words is "twenty-one trillion, one hundred twenty-three billion, four hundred twenty-three million, two hundred twenty-four thousand, five hundred twenty-one".