64757521 has 2 divisors, whose sum is σ = 64757522. Its totient is φ = 64757520.

The previous prime is 64757519. The next prime is 64757549. The reversal of 64757521 is 12575746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49547521 + 15210000 = 7039^2 + 3900^2 .

It is a cyclic number.

It is not a de Polignac number, because 64757521 - 2¹ = 64757519 is a prime.

Together with 64757519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (64757621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32378760 + 32378761.

It is an arithmetic number, because the mean of its divisors is an integer number (32378761).

Almost surely, 2^64757521 is an apocalyptic number.

It is an amenable number.

64757521 is a deficient number, since it is larger than the sum of its proper divisors (1).

64757521 is an equidigital number, since it uses as much as digits as its factorization.

64757521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58800, while the sum is 37.

The square root of 64757521 is about 8047.2057883467. The cubic root of 64757521 is about 401.5719828321.

The spelling of 64757521 in words is "sixty-four million, seven hundred fifty-seven thousand, five hundred twenty-one".