64987621 has 2 divisors, whose sum is σ = 64987622. Its totient is φ = 64987620.

The previous prime is 64987613. The next prime is 64987669. The reversal of 64987621 is 12678946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62631396 + 2356225 = 7914^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 64987621 - 2³ = 64987613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64987721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32493810 + 32493811.

It is an arithmetic number, because the mean of its divisors is an integer number (32493811).

Almost surely, 2^64987621 is an apocalyptic number.

It is an amenable number.

64987621 is a deficient number, since it is larger than the sum of its proper divisors (1).

64987621 is an equidigital number, since it uses as much as digits as its factorization.

64987621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 64987621 is about 8061.4899987533. The cubic root of 64987621 is about 402.0470498465.

The spelling of 64987621 in words is "sixty-four million, nine hundred eighty-seven thousand, six hundred twenty-one".