64521638 has 4 divisors (see below), whose sum is σ = 96782460. Its totient is φ = 32260818.

The previous prime is 64521623. The next prime is 64521641. The reversal of 64521638 is 83612546.

64521638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83612546 = 2 ⋅41806273.

It is a junction number, because it is equal to n+sod(n) for n = 64521598 and 64521607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16130408 + ... + 16130411.

It is an arithmetic number, because the mean of its divisors is an integer number (24195615).

Almost surely, 2^64521638 is an apocalyptic number.

64521638 is a deficient number, since it is larger than the sum of its proper divisors (32260822).

64521638 is a wasteful number, since it uses less digits than its factorization.

64521638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32260821.

The product of its digits is 34560, while the sum is 35.

The square root of 64521638 is about 8032.5362121811. The cubic root of 64521638 is about 401.0838065893.

The spelling of 64521638 in words is "sixty-four million, five hundred twenty-one thousand, six hundred thirty-eight".