21535453405 has 4 divisors (see below), whose sum is σ = 25842544092. Its totient is φ = 17228362720.

The previous prime is 21535453391. The next prime is 21535453421. The reversal of 21535453405 is 50435453512.

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 4666119481 + 16869333924 = 68309^2 + 129882^2 .

It is not a de Polignac number, because 21535453405 - 2¹³ = 21535445213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153545336 + ... + 2153545345.

It is an arithmetic number, because the mean of its divisors is an integer number (6460636023).

Almost surely, 2^21535453405 is an apocalyptic number.

It is an amenable number.

21535453405 is a deficient number, since it is larger than the sum of its proper divisors (4307090687).

21535453405 is an equidigital number, since it uses as much as digits as its factorization.

21535453405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4307090686.

The product of its (nonzero) digits is 180000, while the sum is 37.

The spelling of 21535453405 in words is "twenty-one billion, five hundred thirty-five million, four hundred fifty-three thousand, four hundred five".