640348361 has 4 divisors (see below), whose sum is σ = 649367424. Its totient is φ = 631329300.

The previous prime is 640348273. The next prime is 640348363. The reversal of 640348361 is 163843046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 163843046 = 2 ⋅81921523.

It is a cyclic number.

It is not a de Polignac number, because 640348361 - 2²⁶ = 573239497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640348363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4509425 + ... + 4509566.

It is an arithmetic number, because the mean of its divisors is an integer number (162341856).

Almost surely, 2^640348361 is an apocalyptic number.

It is an amenable number.

640348361 is a deficient number, since it is larger than the sum of its proper divisors (9019063).

640348361 is an equidigital number, since it uses as much as digits as its factorization.

640348361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9019062.

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 640348361 is about 25305.1054334891. The cubic root of 640348361 is about 861.9302061984.

The spelling of 640348361 in words is "six hundred forty million, three hundred forty-eight thousand, three hundred sixty-one".