21235435373 has 4 divisors (see below), whose sum is σ = 21235748700. Its totient is φ = 21235122048.

The previous prime is 21235435357. The next prime is 21235435381. The reversal of 21235435373 is 37353453212.

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 18080029444 + 3155405929 = 134462^2 + 56173^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235435373 - 2⁴ = 21235435357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21235435393) 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, 7940 + ... + 206237.

It is an arithmetic number, because the mean of its divisors is an integer number (5308937175).

Almost surely, 2^21235435373 is an apocalyptic number.

It is an amenable number.

21235435373 is a deficient number, since it is larger than the sum of its proper divisors (313327).

21235435373 is an equidigital number, since it uses as much as digits as its factorization.

21235435373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313326.

The product of its digits is 226800, while the sum is 38.

Adding to 21235435373 its reverse (37353453212), we get a palindrome (58588888585).

The spelling of 21235435373 in words is "twenty-one billion, two hundred thirty-five million, four hundred thirty-five thousand, three hundred seventy-three".