64971440 has 40 divisors (see below), whose sum is σ = 151396560. Its totient is φ = 25930496.

The previous prime is 64971421. The next prime is 64971457. The reversal of 64971440 is 4417946.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 64971440.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63251 + ... + 64269.

It is an arithmetic number, because the mean of its divisors is an integer number (3784914).

Almost surely, 2^64971440 is an apocalyptic number.

It is an amenable number.

64971440 is an abundant number, since it is smaller than the sum of its proper divisors (86425120).

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

64971440 is a wasteful number, since it uses less digits than its factorization.

64971440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829 (or 1823 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 64971440 is about 8060.4863376846. The cubic root of 64971440 is about 402.0136790639.

The spelling of 64971440 in words is "sixty-four million, nine hundred seventy-one thousand, four hundred forty".