21761707664 has 10 divisors (see below), whose sum is σ = 42163308630. Its totient is φ = 10880853824.

The previous prime is 21761707663. The next prime is 21761707687. The reversal of 21761707664 is 46670716712.

It can be written as a sum of positive squares in only one way, i.e., 21758610064 + 3097600 = 147508^2 + 1760^2 .

It is not an unprimeable number, because it can be changed into a prime (21761707661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 680053349 + ... + 680053380.

It is an arithmetic number, because the mean of its divisors is an integer number (4216330863).

Almost surely, 2^21761707664 is an apocalyptic number.

It is an amenable number.

21761707664 is a deficient number, since it is larger than the sum of its proper divisors (20401600966).

21761707664 is a wasteful number, since it uses less digits than its factorization.

21761707664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1360106737 (or 1360106731 counting only the distinct ones).

The product of its (nonzero) digits is 592704, while the sum is 47.

The spelling of 21761707664 in words is "twenty-one billion, seven hundred sixty-one million, seven hundred seven thousand, six hundred sixty-four".