21558787854 has 32 divisors (see below), whose sum is σ = 45363005856. Its totient is φ = 6821498880.

The previous prime is 21558787849. The next prime is 21558787867. The reversal of 21558787854 is 45878785512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1175187 + ... + 1193390.

It is an arithmetic number, because the mean of its divisors is an integer number (1417593933).

Almost surely, 2^21558787854 is an apocalyptic number.

21558787854 is an abundant number, since it is smaller than the sum of its proper divisors (23804218002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21558787854 is a wasteful number, since it uses less digits than its factorization.

21558787854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2368660.

The product of its digits is 25088000, while the sum is 60.

The spelling of 21558787854 in words is "twenty-one billion, five hundred fifty-eight million, seven hundred eighty-seven thousand, eight hundred fifty-four".