21356655354005 has 4 divisors (see below), whose sum is σ = 25627986424812. Its totient is φ = 17085324283200.

The previous prime is 21356655353989. The next prime is 21356655354017. The reversal of 21356655354005 is 50045355665312.

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 13307626753444 + 8049028600561 = 3647962^2 + 2837081^2 .

It is not a de Polignac number, because 21356655354005 - 2⁴ = 21356655353989 is a prime.

It is a super-2 number, since 2×21356655354005² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon 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, 2135665535396 + ... + 2135665535405.

It is an arithmetic number, because the mean of its divisors is an integer number (6406996606203).

Almost surely, 2^{21356655354005} is an apocalyptic number.

It is an amenable number.

21356655354005 is a deficient number, since it is larger than the sum of its proper divisors (4271331070807).

21356655354005 is an equidigital number, since it uses as much as digits as its factorization.

21356655354005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4271331070806.

The product of its (nonzero) digits is 8100000, while the sum is 50.

The spelling of 21356655354005 in words is "twenty-one trillion, three hundred fifty-six billion, six hundred fifty-five million, three hundred fifty-four thousand, five".