21356211550665 has 32 divisors (see below), whose sum is σ = 34325563620096. Its totient is φ = 11338181832960.

The previous prime is 21356211550631. The next prime is 21356211550703. The reversal of 21356211550665 is 56605511265312.

It is not a de Polignac number, because 21356211550665 - 2¹² = 21356211546569 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 1999135 + ... + 6834395.

It is an arithmetic number, because the mean of its divisors is an integer number (1072673863128).

Almost surely, 2^{21356211550665} is an apocalyptic number.

It is an amenable number.

21356211550665 is a deficient number, since it is larger than the sum of its proper divisors (12969352069431).

21356211550665 is a wasteful number, since it uses less digits than its factorization.

21356211550665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4836609.

The product of its (nonzero) digits is 1620000, while the sum is 48.

The spelling of 21356211550665 in words is "twenty-one trillion, three hundred fifty-six billion, two hundred eleven million, five hundred fifty thousand, six hundred sixty-five".