21661331704 has 16 divisors (see below), whose sum is σ = 40661321400. Its totient is φ = 10818312672.

The previous prime is 21661331701. The next prime is 21661331777. The reversal of 21661331704 is 40713316612.

It is a self number, because there is not a number n which added to its sum of digits gives 21661331704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661331701) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1536694 + ... + 1550725.

Almost surely, 2^21661331704 is an apocalyptic number.

It is an amenable number.

21661331704 is a deficient number, since it is larger than the sum of its proper divisors (18999989696).

21661331704 is a wasteful number, since it uses less digits than its factorization.

21661331704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3088302 (or 3088298 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The spelling of 21661331704 in words is "twenty-one billion, six hundred sixty-one million, three hundred thirty-one thousand, seven hundred four".