640498431 has 8 divisors (see below), whose sum is σ = 860517504. Its totient is φ = 423739160.

The previous prime is 640498429. The next prime is 640498447. The reversal of 640498431 is 134894046.

It is a happy number.

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 640498431 - 2¹ = 640498429 is a prime.

It is a super-2 number, since 2×640498431² = 820476480226923522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640498431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642498431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 814491 + ... + 815276.

It is an arithmetic number, because the mean of its divisors is an integer number (107564688).

Almost surely, 2^640498431 is an apocalyptic number.

640498431 is a deficient number, since it is larger than the sum of its proper divisors (220019073).

640498431 is a wasteful number, since it uses less digits than its factorization.

640498431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1629901.

The product of its (nonzero) digits is 82944, while the sum is 39.

The square root of 640498431 is about 25308.0704716895. The cubic root of 640498431 is about 861.9975340107.

The spelling of 640498431 in words is "six hundred forty million, four hundred ninety-eight thousand, four hundred thirty-one".