645122642 has 4 divisors (see below), whose sum is σ = 967683966. Its totient is φ = 322561320.

The previous prime is 645122633. The next prime is 645122689. The reversal of 645122642 is 246221546.

645122642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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., 637108081 + 8014561 = 25241^2 + 2831^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645122599 and 645122608.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161280659 + ... + 161280662.

Almost surely, 2^645122642 is an apocalyptic number.

645122642 is a deficient number, since it is larger than the sum of its proper divisors (322561324).

645122642 is a wasteful number, since it uses less digits than its factorization.

645122642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322561323.

The product of its digits is 23040, while the sum is 32.

The square root of 645122642 is about 25399.2645956532. The cubic root of 645122642 is about 864.0670181568.

The spelling of 645122642 in words is "six hundred forty-five million, one hundred twenty-two thousand, six hundred forty-two".