21730745566 has 16 divisors (see below), whose sum is σ = 33727253040. Its totient is φ = 10488486400.

The previous prime is 21730745549. The next prime is 21730745581. The reversal of 21730745566 is 66554703712.

It is a congruent 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, 255870 + ... + 330046.

It is an arithmetic number, because the mean of its divisors is an integer number (2107953315).

Almost surely, 2^21730745566 is an apocalyptic number.

21730745566 is a deficient number, since it is larger than the sum of its proper divisors (11996507474).

21730745566 is a wasteful number, since it uses less digits than its factorization.

21730745566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79259.

The product of its (nonzero) digits is 1058400, while the sum is 46.

The spelling of 21730745566 in words is "twenty-one billion, seven hundred thirty million, seven hundred forty-five thousand, five hundred sixty-six".