640001553 has 8 divisors (see below), whose sum is σ = 869436288. Its totient is φ = 418617264.

The previous prime is 640001501. The next prime is 640001573. The reversal of 640001553 is 355100046.

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

It is not a de Polignac number, because 640001553 - 2¹⁷ = 639870481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640001573) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2012425 + ... + 2012742.

It is an arithmetic number, because the mean of its divisors is an integer number (108679536).

Almost surely, 2^640001553 is an apocalyptic number.

It is an amenable number.

640001553 is a deficient number, since it is larger than the sum of its proper divisors (229434735).

640001553 is a wasteful number, since it uses less digits than its factorization.

640001553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4025223.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 640001553 is about 25298.2519751860. The cubic root of 640001553 is about 861.7745730616.

Adding to 640001553 its reverse (355100046), we get a palindrome (995101599).

The spelling of 640001553 in words is "six hundred forty million, one thousand, five hundred fifty-three".