64521015 has 16 divisors (see below), whose sum is σ = 111175008. Its totient is φ = 31764096.

The previous prime is 64520999. The next prime is 64521029. The reversal of 64521015 is 51012546.

It is not a de Polignac number, because 64521015 - 2⁴ = 64520999 is a prime.

It is a super-2 number, since 2×64521015² = 8325922753260450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165244 + ... + 165633.

It is an arithmetic number, because the mean of its divisors is an integer number (6948438).

Almost surely, 2^64521015 is an apocalyptic number.

64521015 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

64521015 is a deficient number, since it is larger than the sum of its proper divisors (46653993).

64521015 is a wasteful number, since it uses less digits than its factorization.

64521015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330898.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 64521015 is about 8032.4974323058. The cubic root of 64521015 is about 401.0825156734.

The spelling of 64521015 in words is "sixty-four million, five hundred twenty-one thousand, fifteen".