21353434155 has 24 divisors (see below), whose sum is σ = 37057765680. Its totient is φ = 11374607040.

The previous prime is 21353434127. The next prime is 21353434177. The reversal of 21353434155 is 55143435312.

21353434155 is a `hidden beast` number, since 21 + 3 + 53 + 434 + 155 = 666.

It is not a de Polignac number, because 21353434155 - 2⁹ = 21353433643 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 252045 + ... + 325934.

It is an arithmetic number, because the mean of its divisors is an integer number (1544073570).

Almost surely, 2^21353434155 is an apocalyptic number.

21353434155 is a deficient number, since it is larger than the sum of its proper divisors (15704331525).

21353434155 is a wasteful number, since it uses less digits than its factorization.

21353434155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578811 (or 578808 counting only the distinct ones).

The product of its digits is 108000, while the sum is 36.

Adding to 21353434155 its reverse (55143435312), we get a palindrome (76496869467).

The spelling of 21353434155 in words is "twenty-one billion, three hundred fifty-three million, four hundred thirty-four thousand, one hundred fifty-five".