640825471 has 16 divisors (see below), whose sum is σ = 785594880. Its totient is φ = 514372320.

The previous prime is 640825469. The next prime is 640825477. The reversal of 640825471 is 174528046.

It is not a de Polignac number, because 640825471 - 2¹ = 640825469 is a prime.

It is a super-3 number, since 3×640825471³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640825471.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640825477) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94131 + ... + 100708.

It is an arithmetic number, because the mean of its divisors is an integer number (49099680).

Almost surely, 2^640825471 is an apocalyptic number.

640825471 is a deficient number, since it is larger than the sum of its proper divisors (144769409).

640825471 is a wasteful number, since it uses less digits than its factorization.

640825471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194886.

The product of its (nonzero) digits is 53760, while the sum is 37.

The square root of 640825471 is about 25314.5308271751. The cubic root of 640825471 is about 862.1442217009.

The spelling of 640825471 in words is "six hundred forty million, eight hundred twenty-five thousand, four hundred seventy-one".