64138643 has 4 divisors (see below), whose sum is σ = 64160088. Its totient is φ = 64117200.

The previous prime is 64138621. The next prime is 64138663. The reversal of 64138643 is 34683146.

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

It is a cyclic number.

It is not a de Polignac number, because 64138643 - 2²⁴ = 47361427 is a prime.

It is a super-2 number, since 2×64138643² = 8227531051762898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64138663) 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, 5333 + ... + 12518.

It is an arithmetic number, because the mean of its divisors is an integer number (16040022).

Almost surely, 2^64138643 is an apocalyptic number.

64138643 is a deficient number, since it is larger than the sum of its proper divisors (21445).

64138643 is a wasteful number, since it uses less digits than its factorization.

64138643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21444.

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

The square root of 64138643 is about 8008.6604997340. The cubic root of 64138643 is about 400.2886312632.

The spelling of 64138643 in words is "sixty-four million, one hundred thirty-eight thousand, six hundred forty-three".