640450641 has 8 divisors (see below), whose sum is σ = 854352864. Its totient is φ = 426757760.

The previous prime is 640450637. The next prime is 640450661. The reversal of 640450641 is 146054046.

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 640450641 - 2² = 640450637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640450599 and 640450608.

It is not an unprimeable number, because it can be changed into a prime (640450631) 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, 45051 + ... + 57536.

It is an arithmetic number, because the mean of its divisors is an integer number (106794108).

Almost surely, 2^640450641 is an apocalyptic number.

It is an amenable number.

640450641 is a deficient number, since it is larger than the sum of its proper divisors (213902223).

640450641 is a wasteful number, since it uses less digits than its factorization.

640450641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104671.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 640450641 is about 25307.1262888539. The cubic root of 640450641 is about 861.9760945167.

The spelling of 640450641 in words is "six hundred forty million, four hundred fifty thousand, six hundred forty-one".