64843640 has 32 divisors (see below), whose sum is σ = 146556000. Its totient is φ = 25820544.

The previous prime is 64843633. The next prime is 64843643. The reversal of 64843640 is 4634846.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 64843640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64843643) 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, 5621 + ... + 12699.

It is an arithmetic number, because the mean of its divisors is an integer number (4579875).

Almost surely, 2^64843640 is an apocalyptic number.

It is an amenable number.

64843640 is an abundant number, since it is smaller than the sum of its proper divisors (81712360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64843640 is a wasteful number, since it uses less digits than its factorization.

64843640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7319 (or 7315 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 35.

The square root of 64843640 is about 8052.5548740757. The cubic root of 64843640 is about 401.7499166489.

The spelling of 64843640 in words is "sixty-four million, eight hundred forty-three thousand, six hundred forty".