21356143667646 has 16 divisors (see below), whose sum is σ = 42713321201424. Its totient is φ = 7118542244864.

The previous prime is 21356143667597. The next prime is 21356143667689. The reversal of 21356143667646 is 64676634165312.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21356143667646.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42809091 + ... + 43305086.

It is an arithmetic number, because the mean of its divisors is an integer number (2669582575089).

Almost surely, 2^{21356143667646} is an apocalyptic number.

21356143667646 is an abundant number, since it is smaller than the sum of its proper divisors (21357177533778).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21356143667646 is a wasteful number, since it uses less digits than its factorization.

21356143667646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86155515.

The product of its digits is 78382080, while the sum is 60.

The spelling of 21356143667646 in words is "twenty-one trillion, three hundred fifty-six billion, one hundred forty-three million, six hundred sixty-seven thousand, six hundred forty-six".