645442057 has 8 divisors (see below), whose sum is σ = 698211584. Its totient is φ = 593118288.

The previous prime is 645442051. The next prime is 645442079. The reversal of 645442057 is 750244546.

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

It is a cyclic number.

It is not a de Polignac number, because 645442057 - 2¹¹ = 645440009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645442051) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 108423 + ... + 114220.

It is an arithmetic number, because the mean of its divisors is an integer number (87276448).

Almost surely, 2^645442057 is an apocalyptic number.

It is an amenable number.

645442057 is a deficient number, since it is larger than the sum of its proper divisors (52769527).

645442057 is a wasteful number, since it uses less digits than its factorization.

645442057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222879.

The product of its (nonzero) digits is 134400, while the sum is 37.

The square root of 645442057 is about 25405.5516964304. The cubic root of 645442057 is about 864.2096010863.

The spelling of 645442057 in words is "six hundred forty-five million, four hundred forty-two thousand, fifty-seven".