21621405000353 has 4 divisors (see below), whose sum is σ = 21636004194948. Its totient is φ = 21606805805760.

The previous prime is 21621405000347. The next prime is 21621405000413. The reversal of 21621405000353 is 35300050412612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9685091719744 + 11936313280609 = 3112088^2 + 3454897^2 .

It is a cyclic number.

It is not a de Polignac number, because 21621405000353 - 2¹⁰ = 21621404999329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621405050353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7299595076 + ... + 7299598037.

It is an arithmetic number, because the mean of its divisors is an integer number (5409001048737).

Almost surely, 2^{21621405000353} is an apocalyptic number.

It is an amenable number.

21621405000353 is a deficient number, since it is larger than the sum of its proper divisors (14599194595).

21621405000353 is a wasteful number, since it uses less digits than its factorization.

21621405000353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14599194594.

The product of its (nonzero) digits is 21600, while the sum is 32.

Adding to 21621405000353 its reverse (35300050412612), we get a palindrome (56921455412965).

The spelling of 21621405000353 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred five million, three hundred fifty-three", and thus it is an aban number.