645042642 has 8 divisors (see below), whose sum is σ = 1290085296. Its totient is φ = 215014212.

The previous prime is 645042631. The next prime is 645042649. The reversal of 645042642 is 246240546.

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

645042642 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (645042649) 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, 53753548 + ... + 53753559.

It is an arithmetic number, because the mean of its divisors is an integer number (161260662).

Almost surely, 2^645042642 is an apocalyptic number.

645042642 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645042642 is a wasteful number, since it uses less digits than its factorization.

645042642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107507112.

The product of its (nonzero) digits is 46080, while the sum is 33.

The square root of 645042642 is about 25397.6896980808. The cubic root of 645042642 is about 864.0312997706.

The spelling of 645042642 in words is "six hundred forty-five million, forty-two thousand, six hundred forty-two".