64691397 has 6 divisors (see below), whose sum is σ = 93443142. Its totient is φ = 43127592.

The previous prime is 64691383. The next prime is 64691413. The reversal of 64691397 is 79319646.

It can be written as a sum of positive squares in only one way, i.e., 54154881 + 10536516 = 7359^2 + 3246^2 .

It is a de Polignac number, because none of the positive numbers 2^k-64691397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64691357) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3593958 + ... + 3593975.

It is an arithmetic number, because the mean of its divisors is an integer number (15573857).

Almost surely, 2^64691397 is an apocalyptic number.

It is an amenable number.

64691397 is a deficient number, since it is larger than the sum of its proper divisors (28751745).

64691397 is a wasteful number, since it uses less digits than its factorization.

64691397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7187939 (or 7187936 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 64691397 is about 8043.0962321733. The cubic root of 64691397 is about 401.4352543694.

The spelling of 64691397 in words is "sixty-four million, six hundred ninety-one thousand, three hundred ninety-seven".