21750646858 has 4 divisors (see below), whose sum is σ = 32625970290. Its totient is φ = 10875323428.

The previous prime is 21750646849. The next prime is 21750646861. The reversal of 21750646858 is 85864605712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11202740649 + 10547906209 = 105843^2 + 102703^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5437661713 + ... + 5437661716.

Almost surely, 2^21750646858 is an apocalyptic number.

21750646858 is a deficient number, since it is larger than the sum of its proper divisors (10875323432).

21750646858 is a wasteful number, since it uses less digits than its factorization.

21750646858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10875323431.

The product of its (nonzero) digits is 3225600, while the sum is 52.

The spelling of 21750646858 in words is "twenty-one billion, seven hundred fifty million, six hundred forty-six thousand, eight hundred fifty-eight".