645142661770 has 8 divisors (see below), whose sum is σ = 1161256791204. Its totient is φ = 258057064704.

The previous prime is 645142661767. The next prime is 645142661771. The reversal of 645142661770 is 77166241546.

It can be written as a sum of positive squares in 2 ways, for example, as 622033493481 + 23109168289 = 788691^2 + 152017^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (645142661771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32257133079 + ... + 32257133098.

Almost surely, 2^645142661770 is an apocalyptic number.

645142661770 is a deficient number, since it is larger than the sum of its proper divisors (516114129434).

645142661770 is a wasteful number, since it uses less digits than its factorization.

645142661770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64514266184.

The product of its (nonzero) digits is 1693440, while the sum is 49.

The spelling of 645142661770 in words is "six hundred forty-five billion, one hundred forty-two million, six hundred sixty-one thousand, seven hundred seventy".