21345435555 has 16 divisors (see below), whose sum is σ = 34160071680. Its totient is φ = 11381774048.

The previous prime is 21345435521. The next prime is 21345435557. The reversal of 21345435555 is 55553454312.

It is a cyclic number.

It is not a de Polignac number, because 21345435555 - 2⁹ = 21345435043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21345435557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80745 + ... + 221834.

It is an arithmetic number, because the mean of its divisors is an integer number (2135004480).

Almost surely, 2^21345435555 is an apocalyptic number.

21345435555 is a deficient number, since it is larger than the sum of its proper divisors (12814636125).

21345435555 is a wasteful number, since it uses less digits than its factorization.

21345435555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307290.

The product of its digits is 900000, while the sum is 42.

Adding to 21345435555 its reverse (55553454312), we get a palindrome (76898889867).

The spelling of 21345435555 in words is "twenty-one billion, three hundred forty-five million, four hundred thirty-five thousand, five hundred fifty-five".