64377521 has 16 divisors (see below), whose sum is σ = 75401424. Its totient is φ = 54411264.

The previous prime is 64377499. The next prime is 64377541. The reversal of 64377521 is 12577346.

It can be written as a sum of positive squares in 8 ways, for example, as 1000000 + 63377521 = 1000^2 + 7961^2 .

It is a cyclic number.

It is not a de Polignac number, because 64377521 - 2¹⁰ = 64376497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64377541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4241 + ... + 12113.

It is an arithmetic number, because the mean of its divisors is an integer number (4712589).

Almost surely, 2^64377521 is an apocalyptic number.

It is an amenable number.

64377521 is a deficient number, since it is larger than the sum of its proper divisors (11023903).

64377521 is a wasteful number, since it uses less digits than its factorization.

64377521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7940.

The product of its digits is 35280, while the sum is 35.

The square root of 64377521 is about 8023.5603693124. The cubic root of 64377521 is about 400.7849606676.

The spelling of 64377521 in words is "sixty-four million, three hundred seventy-seven thousand, five hundred twenty-one".