64545721 has 2 divisors, whose sum is σ = 64545722. Its totient is φ = 64545720.

The previous prime is 64545707. The next prime is 64545727. The reversal of 64545721 is 12754546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47073321 + 17472400 = 6861^2 + 4180^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64545721 is a prime.

It is not a weakly prime, because it can be changed into another prime (64545727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32272860 + 32272861.

It is an arithmetic number, because the mean of its divisors is an integer number (32272861).

Almost surely, 2^64545721 is an apocalyptic number.

It is an amenable number.

64545721 is a deficient number, since it is larger than the sum of its proper divisors (1).

64545721 is an equidigital number, since it uses as much as digits as its factorization.

64545721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 34.

The square root of 64545721 is about 8034.0351629801. The cubic root of 64545721 is about 401.1337025109.

The spelling of 64545721 in words is "sixty-four million, five hundred forty-five thousand, seven hundred twenty-one".