21666853442 has 16 divisors (see below), whose sum is σ = 35002746240. Its totient is φ = 9999387792.

The previous prime is 21666853423. The next prime is 21666853451. The reversal of 21666853442 is 24435866612.

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, 644609 + ... + 677387.

It is an arithmetic number, because the mean of its divisors is an integer number (2187671640).

Almost surely, 2^21666853442 is an apocalyptic number.

21666853442 is a deficient number, since it is larger than the sum of its proper divisors (13335892798).

21666853442 is a wasteful number, since it uses less digits than its factorization.

21666853442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58217.

The product of its digits is 1658880, while the sum is 47.

The spelling of 21666853442 in words is "twenty-one billion, six hundred sixty-six million, eight hundred fifty-three thousand, four hundred forty-two".