21688545854 has 8 divisors (see below), whose sum is σ = 32748268368. Its totient is φ = 10772456400.

The previous prime is 21688545817. The next prime is 21688545859. The reversal of 21688545854 is 45854588612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21688545854² (a number of 21 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 21688545854.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21688545859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35907887 + ... + 35908490.

It is an arithmetic number, because the mean of its divisors is an integer number (4093533546).

Almost surely, 2^21688545854 is an apocalyptic number.

21688545854 is a deficient number, since it is larger than the sum of its proper divisors (11059722514).

21688545854 is a wasteful number, since it uses less digits than its factorization.

21688545854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71816530.

The product of its digits is 12288000, while the sum is 56.

The spelling of 21688545854 in words is "twenty-one billion, six hundred eighty-eight million, five hundred forty-five thousand, eight hundred fifty-four".