21253042503405 has 48 divisors (see below), whose sum is σ = 38460768727680. Its totient is φ = 10836354528384.

The previous prime is 21253042503397. The next prime is 21253042503431. The reversal of 21253042503405 is 50430524035212.

21253042503405 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 304 + 2 + 5 + 0 + 340 + 5 = 666.

It is not a de Polignac number, because 21253042503405 - 2³ = 21253042503397 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21253042503405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3527295 + ... + 7412684.

It is an arithmetic number, because the mean of its divisors is an integer number (801266015160).

Almost surely, 2^{21253042503405} is an apocalyptic number.

It is an amenable number.

21253042503405 is a deficient number, since it is larger than the sum of its proper divisors (17207726224275).

21253042503405 is a wasteful number, since it uses less digits than its factorization.

21253042503405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10941890 (or 10941887 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 36.

Adding to 21253042503405 its reverse (50430524035212), we get a palindrome (71683566538617).

The spelling of 21253042503405 in words is "twenty-one trillion, two hundred fifty-three billion, forty-two million, five hundred three thousand, four hundred five".