645722161796 has 12 divisors (see below), whose sum is σ = 1130019932160. Its totient is φ = 322859324040.

The previous prime is 645722161781. The next prime is 645722161807. The reversal of 645722161796 is 697161227546.

It is a happy number.

It is a super-2 number, since 2×645722161796² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 738845 + ... + 1355483.

It is an arithmetic number, because the mean of its divisors is an integer number (94168327680).

Almost surely, 2^645722161796 is an apocalyptic number.

It is an amenable number.

645722161796 is a deficient number, since it is larger than the sum of its proper divisors (484297770364).

645722161796 is a wasteful number, since it uses less digits than its factorization.

645722161796 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878434 (or 878432 counting only the distinct ones).

The product of its digits is 7620480, while the sum is 56.

The spelling of 645722161796 in words is "six hundred forty-five billion, seven hundred twenty-two million, one hundred sixty-one thousand, seven hundred ninety-six".