64521603 has 28 divisors (see below), whose sum is σ = 98256328. Its totient is φ = 42340320.

The previous prime is 64521593. The next prime is 64521623. The reversal of 64521603 is 30612546.

64521603 is a `hidden beast` number, since 6 + 4 + 52 + 1 + 603 = 666.

It is not a de Polignac number, because 64521603 - 2⁶ = 64521539 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64521623) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 48183 + ... + 49503.

Almost surely, 2^64521603 is an apocalyptic number.

64521603 is a deficient number, since it is larger than the sum of its proper divisors (33734725).

64521603 is an equidigital number, since it uses as much as digits as its factorization.

64521603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1406 (or 1391 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 64521603 is about 8032.5340335413. The cubic root of 64521603 is about 401.0837340661.

The spelling of 64521603 in words is "sixty-four million, five hundred twenty-one thousand, six hundred three".