21568916418 has 16 divisors (see below), whose sum is σ = 49300380480. Its totient is φ = 6162547536.

The previous prime is 21568916393. The next prime is 21568916423. The reversal of 21568916418 is 81461986512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 256772773 + ... + 256772856.

It is an arithmetic number, because the mean of its divisors is an integer number (3081273780).

Almost surely, 2^21568916418 is an apocalyptic number.

21568916418 is an abundant number, since it is smaller than the sum of its proper divisors (27731464062).

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

21568916418 is a wasteful number, since it uses less digits than its factorization.

21568916418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513545641.

The product of its digits is 829440, while the sum is 51.

The spelling of 21568916418 in words is "twenty-one billion, five hundred sixty-eight million, nine hundred sixteen thousand, four hundred eighteen".