21076556686 has 4 divisors (see below), whose sum is σ = 31614835032. Its totient is φ = 10538278342.

The previous prime is 21076556663. The next prime is 21076556723. The reversal of 21076556686 is 68665567012.

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

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5269139170 + ... + 5269139173.

It is an arithmetic number, because the mean of its divisors is an integer number (7903708758).

Almost surely, 2^21076556686 is an apocalyptic number.

21076556686 is a deficient number, since it is larger than the sum of its proper divisors (10538278346).

21076556686 is a wasteful number, since it uses less digits than its factorization.

21076556686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10538278345.

The product of its (nonzero) digits is 3628800, while the sum is 52.

The spelling of 21076556686 in words is "twenty-one billion, seventy-six million, five hundred fifty-six thousand, six hundred eighty-six".