21135433153 has 4 divisors (see below), whose sum is σ = 21372910020. Its totient is φ = 20897956288.

The previous prime is 21135433139. The next prime is 21135433181. The reversal of 21135433153 is 35133453112.

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 7867157809 + 13268275344 = 88697^2 + 115188^2 .

It is a cyclic number.

It is not a de Polignac number, because 21135433153 - 2⁹ = 21135432641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21135433183) 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, 118738300 + ... + 118738477.

It is an arithmetic number, because the mean of its divisors is an integer number (5343227505).

Almost surely, 2^21135433153 is an apocalyptic number.

It is an amenable number.

21135433153 is a deficient number, since it is larger than the sum of its proper divisors (237476867).

21135433153 is an equidigital number, since it uses as much as digits as its factorization.

21135433153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237476866.

The product of its digits is 16200, while the sum is 31.

Adding to 21135433153 its reverse (35133453112), we get a palindrome (56268886265).

The spelling of 21135433153 in words is "twenty-one billion, one hundred thirty-five million, four hundred thirty-three thousand, one hundred fifty-three".