64640434 has 4 divisors (see below), whose sum is σ = 96960654. Its totient is φ = 32320216.

The previous prime is 64640399. The next prime is 64640437. The reversal of 64640434 is 43404646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 43404646 = 2 ⋅21702323.

It can be written as a sum of positive squares in only one way, i.e., 38477209 + 26163225 = 6203^2 + 5115^2 .

It is a junction number, because it is equal to n+sod(n) for n = 64640396 and 64640405.

It is not an unprimeable number, because it can be changed into a prime (64640437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16160107 + ... + 16160110.

Almost surely, 2^64640434 is an apocalyptic number.

64640434 is a deficient number, since it is larger than the sum of its proper divisors (32320220).

64640434 is a wasteful number, since it uses less digits than its factorization.

64640434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32320219.

The product of its (nonzero) digits is 27648, while the sum is 31.

The square root of 64640434 is about 8039.9274872352. The cubic root of 64640434 is about 401.3298116035.

The spelling of 64640434 in words is "sixty-four million, six hundred forty thousand, four hundred thirty-four".