637861721066 has 16 divisors (see below), whose sum is σ = 963698843520. Its totient is φ = 316636837440.

The previous prime is 637861721023. The next prime is 637861721071. The reversal of 637861721066 is 660127168736.

It is a junction number, because it is equal to n+sod(n) for n = 637861720999 and 637861721017.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1857551 + ... + 2173986.

It is an arithmetic number, because the mean of its divisors is an integer number (60231177720).

Almost surely, 2^637861721066 is an apocalyptic number.

637861721066 is a deficient number, since it is larger than the sum of its proper divisors (325837122454).

637861721066 is a wasteful number, since it uses less digits than its factorization.

637861721066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4032109.

The product of its (nonzero) digits is 3048192, while the sum is 53.

The spelling of 637861721066 in words is "six hundred thirty-seven billion, eight hundred sixty-one million, seven hundred twenty-one thousand, sixty-six".