640072657534 has 4 divisors (see below), whose sum is σ = 960108986304. Its totient is φ = 320036328766.

The previous prime is 640072657531. The next prime is 640072657541. The reversal of 640072657534 is 435756270046.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×640072657534² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640072657531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160018164382 + ... + 160018164385.

It is an arithmetic number, because the mean of its divisors is an integer number (240027246576).

Almost surely, 2^640072657534 is an apocalyptic number.

640072657534 is a deficient number, since it is larger than the sum of its proper divisors (320036328770).

640072657534 is a wasteful number, since it uses less digits than its factorization.

640072657534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320036328769.

The product of its (nonzero) digits is 4233600, while the sum is 49.

The spelling of 640072657534 in words is "six hundred forty billion, seventy-two million, six hundred fifty-seven thousand, five hundred thirty-four".