64780621 has 4 divisors (see below), whose sum is σ = 64872700. Its totient is φ = 64688544.

The previous prime is 64780609. The next prime is 64780631. The reversal of 64780621 is 12608746.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36542025 + 28238596 = 6045^2 + 5314^2 .

It is a cyclic number.

It is not a de Polignac number, because 64780621 - 2⁵ = 64780589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64780631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44976 + ... + 46393.

It is an arithmetic number, because the mean of its divisors is an integer number (16218175).

Almost surely, 2^64780621 is an apocalyptic number.

It is an amenable number.

64780621 is a deficient number, since it is larger than the sum of its proper divisors (92079).

64780621 is an equidigital number, since it uses as much as digits as its factorization.

64780621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92078.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 64780621 is about 8048.6409411776. The cubic root of 64780621 is about 401.6197261154.

The spelling of 64780621 in words is "sixty-four million, seven hundred eighty thousand, six hundred twenty-one".