64015621 has 2 divisors, whose sum is σ = 64015622. Its totient is φ = 64015620.

The previous prime is 64015613. The next prime is 64015631. The reversal of 64015621 is 12651046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42393121 + 21622500 = 6511^2 + 4650^2 .

It is a cyclic number.

It is not a de Polignac number, because 64015621 - 2³ = 64015613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64015631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32007810 + 32007811.

It is an arithmetic number, because the mean of its divisors is an integer number (32007811).

Almost surely, 2^64015621 is an apocalyptic number.

It is an amenable number.

64015621 is a deficient number, since it is larger than the sum of its proper divisors (1).

64015621 is an equidigital number, since it uses as much as digits as its factorization.

64015621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 64015621 is about 8000.9762529331. The cubic root of 64015621 is about 400.0325411026.

Adding to 64015621 its reverse (12651046), we get a palindrome (76666667).

It can be divided in two parts, 640 and 15621, that added together give a palindrome (16261).

The spelling of 64015621 in words is "sixty-four million, fifteen thousand, six hundred twenty-one".