21216565521463 has 16 divisors (see below), whose sum is σ = 23085988480800. Its totient is φ = 19381241404800.

The previous prime is 21216565521397. The next prime is 21216565521509. The reversal of 21216565521463 is 36412556561212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21216565521463 is a prime.

It is a super-2 number, since 2×21216565521463² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216565524463) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1188393 + ... + 6621586.

It is an arithmetic number, because the mean of its divisors is an integer number (1442874280050).

Almost surely, 2^{21216565521463} is an apocalyptic number.

21216565521463 is a deficient number, since it is larger than the sum of its proper divisors (1869422959337).

21216565521463 is a wasteful number, since it uses less digits than its factorization.

21216565521463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7812162.

The product of its digits is 2592000, while the sum is 49.

The spelling of 21216565521463 in words is "twenty-one trillion, two hundred sixteen billion, five hundred sixty-five million, five hundred twenty-one thousand, four hundred sixty-three".