21554347178 has 32 divisors (see below), whose sum is σ = 40186661760. Its totient is φ = 8442561600.

The previous prime is 21554347169. The next prime is 21554347183. The reversal of 21554347178 is 87174345512.

It is a Smith number, since the sum of its digits (47) 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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 567908 + ... + 604671.

It is an arithmetic number, because the mean of its divisors is an integer number (1255833180).

Almost surely, 2^21554347178 is an apocalyptic number.

21554347178 is a deficient number, since it is larger than the sum of its proper divisors (18632314582).

21554347178 is a wasteful number, since it uses less digits than its factorization.

21554347178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172702.

The product of its digits is 940800, while the sum is 47.

It can be divided in two parts, 2155434 and 7178, that added together give a palindrome (2162612).

The spelling of 21554347178 in words is "twenty-one billion, five hundred fifty-four million, three hundred forty-seven thousand, one hundred seventy-eight".