21207677186 has 4 divisors (see below), whose sum is σ = 31811515782. Its totient is φ = 10603838592.

The previous prime is 21207677173. The next prime is 21207677201. The reversal of 21207677186 is 68177670212.

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., 14986411561 + 6221265625 = 122419^2 + 78875^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21207677186.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5301919295 + ... + 5301919298.

Almost surely, 2^21207677186 is an apocalyptic number.

21207677186 is a deficient number, since it is larger than the sum of its proper divisors (10603838596).

21207677186 is a wasteful number, since it uses less digits than its factorization.

21207677186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10603838595.

The product of its (nonzero) digits is 395136, while the sum is 47.

The spelling of 21207677186 in words is "twenty-one billion, two hundred seven million, six hundred seventy-seven thousand, one hundred eighty-six".