640453780438 has 8 divisors (see below), whose sum is σ = 960789040632. Its totient is φ = 320190766896.

The previous prime is 640453780423. The next prime is 640453780453. The reversal of 640453780438 is 834087354046.

It is an interprime number because it is at equal distance from previous prime (640453780423) and next prime (640453780453).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×640453780438² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18039495 + ... + 18074962.

It is an arithmetic number, because the mean of its divisors is an integer number (120098630079).

Almost surely, 2^640453780438 is an apocalyptic number.

640453780438 is a deficient number, since it is larger than the sum of its proper divisors (320335260194).

640453780438 is a wasteful number, since it uses less digits than its factorization.

640453780438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36123326.

The product of its (nonzero) digits is 7741440, while the sum is 52.

It can be divided in two parts, 64045 and 3780438, that added together give a palindrome (3844483).

The spelling of 640453780438 in words is "six hundred forty billion, four hundred fifty-three million, seven hundred eighty thousand, four hundred thirty-eight".