64400641 has 4 divisors (see below), whose sum is σ = 68188932. Its totient is φ = 60612352.

The previous prime is 64400617. The next prime is 64400659. The reversal of 64400641 is 14600446.

64400641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 50112241 + 14288400 = 7079^2 + 3780^2 .

It is a cyclic number.

It is not a de Polignac number, because 64400641 - 2⁹ = 64400129 is a prime.

It is a super-2 number, since 2×64400641² = 8294885122421762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64400041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1894120 + ... + 1894153.

It is an arithmetic number, because the mean of its divisors is an integer number (17047233).

Almost surely, 2^64400641 is an apocalyptic number.

It is an amenable number.

64400641 is a deficient number, since it is larger than the sum of its proper divisors (3788291).

64400641 is a wasteful number, since it uses less digits than its factorization.

64400641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3788290.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 64400641 is about 8025.0009968847. Note that the first 3 decimals coincide. The cubic root of 64400641 is about 400.8329331022.

The spelling of 64400641 in words is "sixty-four million, four hundred thousand, six hundred forty-one".