64639397 has 4 divisors (see below), whose sum is σ = 65735040. Its totient is φ = 63543756.

The previous prime is 64639369. The next prime is 64639403. The reversal of 64639397 is 79393646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 79393646 = 2 ⋅39696823.

It is a cyclic number.

It is not a de Polignac number, because 64639397 - 2¹² = 64635301 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 (64639327) 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, 547733 + ... + 547850.

It is an arithmetic number, because the mean of its divisors is an integer number (16433760).

Almost surely, 2^64639397 is an apocalyptic number.

It is an amenable number.

64639397 is a deficient number, since it is larger than the sum of its proper divisors (1095643).

64639397 is a wasteful number, since it uses less digits than its factorization.

64639397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1095642.

The product of its digits is 734832, while the sum is 47.

The square root of 64639397 is about 8039.8629963451. The cubic root of 64639397 is about 401.3276654688.

The spelling of 64639397 in words is "sixty-four million, six hundred thirty-nine thousand, three hundred ninety-seven".