65409664 has 16 divisors (see below), whose sum is σ = 130308570. Its totient is φ = 32704768.

The previous prime is 65409661. The next prime is 65409667. The reversal of 65409664 is 46690456.

It is an interprime number because it is at equal distance from previous prime (65409661) and next prime (65409667).

It can be written as a sum of positive squares in only one way, i.e., 63872064 + 1537600 = 7992^2 + 1240^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is not an unprimeable number, because it can be changed into a prime (65409661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 255379 + ... + 255634.

Almost surely, 2^65409664 is an apocalyptic number.

65409664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

65409664 is a deficient number, since it is larger than the sum of its proper divisors (64898906).

65409664 is an equidigital number, since it uses as much as digits as its factorization.

65409664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511027 (or 511015 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 65409664 is about 8087.6241257863. The cubic root of 65409664 is about 402.9154980484.

The spelling of 65409664 in words is "sixty-five million, four hundred nine thousand, six hundred sixty-four".