21688561006498 has 64 divisors (see below), whose sum is σ = 35012006092800. Its totient is φ = 10051605748800.

The previous prime is 21688561006477. The next prime is 21688561006507. The reversal of 21688561006498 is 89460016588612.

It is a Smith number, since the sum of its digits (64) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 127082323 + ... + 127252873.

It is an arithmetic number, because the mean of its divisors is an integer number (547062595200).

Almost surely, 2^{21688561006498} is an apocalyptic number.

21688561006498 is a deficient number, since it is larger than the sum of its proper divisors (13323445086302).

21688561006498 is a wasteful number, since it uses less digits than its factorization.

21688561006498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171127.

The product of its (nonzero) digits is 39813120, while the sum is 64.

The spelling of 21688561006498 in words is "twenty-one trillion, six hundred eighty-eight billion, five hundred sixty-one million, six thousand, four hundred ninety-eight".