21145502345421 has 8 divisors (see below), whose sum is σ = 28203920128800. Its totient is φ = 14092043062832.

The previous prime is 21145502345369. The next prime is 21145502345423. The reversal of 21145502345421 is 12454320554112.

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 21145502345421 - 2¹³ = 21145502337229 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21145502345421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145502345423) 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, 1239615246 + ... + 1239632303.

It is an arithmetic number, because the mean of its divisors is an integer number (3525490016100).

Almost surely, 2^{21145502345421} is an apocalyptic number.

It is an amenable number.

21145502345421 is a deficient number, since it is larger than the sum of its proper divisors (7058417783379).

21145502345421 is a wasteful number, since it uses less digits than its factorization.

21145502345421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2479250395.

The product of its (nonzero) digits is 192000, while the sum is 39.

Adding to 21145502345421 its reverse (12454320554112), we get a palindrome (33599822899533).

The spelling of 21145502345421 in words is "twenty-one trillion, one hundred forty-five billion, five hundred two million, three hundred forty-five thousand, four hundred twenty-one".