21655416043365 has 64 divisors (see below), whose sum is σ = 37676013484032. Its totient is φ = 10558014854400.

The previous prime is 21655416043321. The next prime is 21655416043423. The reversal of 21655416043365 is 56334061455612.

It is a happy number.

It is not a de Polignac number, because 21655416043365 - 2⁷ = 21655416043237 is a prime.

It is a super-2 number, since 2×21655416043365² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11570050 + ... + 13310780.

It is an arithmetic number, because the mean of its divisors is an integer number (588687710688).

Almost surely, 2^{21655416043365} is an apocalyptic number.

It is an amenable number.

21655416043365 is a deficient number, since it is larger than the sum of its proper divisors (16020597440667).

21655416043365 is a wasteful number, since it uses less digits than its factorization.

21655416043365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1741370.

The product of its (nonzero) digits is 7776000, while the sum is 51.

Adding to 21655416043365 its reverse (56334061455612), we get a palindrome (77989477498977).

The spelling of 21655416043365 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred sixteen million, forty-three thousand, three hundred sixty-five".