21101217554464 has 24 divisors (see below), whose sum is σ = 41548336998588. Its totient is φ = 10549258951680.

The previous prime is 21101217554449. The next prime is 21101217554491. The reversal of 21101217554464 is 46445571210112.

It can be written as a sum of positive squares in 2 ways, for example, as 15606450250000 + 5494767304464 = 3950500^2 + 2344092^2 .

It is a super-2 number, since 2×21101217554464² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21101217554464.

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, 41927997 + ... + 42428284.

Almost surely, 2^{21101217554464} is an apocalyptic number.

It is an amenable number.

21101217554464 is a deficient number, since it is larger than the sum of its proper divisors (20447119444124).

21101217554464 is an equidigital number, since it uses as much as digits as its factorization.

21101217554464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84364108 (or 84364100 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 43.

Adding to 21101217554464 its reverse (46445571210112), we get a palindrome (67546788764576).

The spelling of 21101217554464 in words is "twenty-one trillion, one hundred one billion, two hundred seventeen million, five hundred fifty-four thousand, four hundred sixty-four".