64640005 has 16 divisors (see below), whose sum is σ = 81160704. Its totient is φ = 49329280.

The previous prime is 64640003. The next prime is 64640011. The reversal of 64640005 is 50004646.

It is a happy number.

It is not a de Polignac number, because 64640005 - 2¹ = 64640003 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70500 + ... + 71410.

It is an arithmetic number, because the mean of its divisors is an integer number (5072544).

Almost surely, 2^64640005 is an apocalyptic number.

It is an amenable number.

64640005 is a deficient number, since it is larger than the sum of its proper divisors (16520699).

64640005 is a wasteful number, since it uses less digits than its factorization.

64640005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 64640005 is about 8039.9008078458. The cubic root of 64640005 is about 401.3289237646.

The spelling of 64640005 in words is "sixty-four million, six hundred forty thousand, five".