645540375 has 16 divisors (see below), whose sum is σ = 1074179808. Its totient is φ = 344288000.

The previous prime is 645540353. The next prime is 645540391. The reversal of 645540375 is 573045546.

645540375 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645540375 - 2⁹ = 645539863 is a prime.

It is a super-3 number, since 3×645540375³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 860346 + ... + 861095.

It is an arithmetic number, because the mean of its divisors is an integer number (67136238).

Almost surely, 2^645540375 is an apocalyptic number.

645540375 is a deficient number, since it is larger than the sum of its proper divisors (428639433).

645540375 is a wasteful number, since it uses less digits than its factorization.

645540375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1721459 (or 1721449 counting only the distinct ones).

The product of its (nonzero) digits is 252000, while the sum is 39.

The square root of 645540375 is about 25407.4865935220. The cubic root of 645540375 is about 864.2534795644.

The spelling of 645540375 in words is "six hundred forty-five million, five hundred forty thousand, three hundred seventy-five".