640535525 has 24 divisors (see below), whose sum is σ = 928851264. Its totient is φ = 429004800.

The previous prime is 640535521. The next prime is 640535573. The reversal of 640535525 is 525535046.

It is not a de Polignac number, because 640535525 - 2² = 640535521 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640535521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35036 + ... + 50085.

It is an arithmetic number, because the mean of its divisors is an integer number (38702136).

Almost surely, 2^640535525 is an apocalyptic number.

It is an amenable number.

640535525 is a deficient number, since it is larger than the sum of its proper divisors (288315739).

640535525 is a wasteful number, since it uses less digits than its factorization.

640535525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85181 (or 85176 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 35.

The square root of 640535525 is about 25308.8033103108. The cubic root of 640535525 is about 862.0141743425.

The spelling of 640535525 in words is "six hundred forty million, five hundred thirty-five thousand, five hundred twenty-five".