64640549 has 8 divisors (see below), whose sum is σ = 67986432. Its totient is φ = 61373520.

The previous prime is 64640539. The next prime is 64640581. The reversal of 64640549 is 94504646.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64640549 is a prime.

It is a super-3 number, since 3×64640549³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640539) 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, 18029 + ... + 21314.

It is an arithmetic number, because the mean of its divisors is an integer number (8498304).

Almost surely, 2^64640549 is an apocalyptic number.

It is an amenable number.

64640549 is a deficient number, since it is larger than the sum of its proper divisors (3345883).

64640549 is a wasteful number, since it uses less digits than its factorization.

64640549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39427.

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 64640549 is about 8039.9346390378. The cubic root of 64640549 is about 401.3300496016.

The spelling of 64640549 in words is "sixty-four million, six hundred forty thousand, five hundred forty-nine".