621649549 has 4 divisors (see below), whose sum is σ = 621774364. Its totient is φ = 621524736.

The previous prime is 621649537. The next prime is 621649559. The reversal of 621649549 is 945946126.

621649549 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 319515625 + 302133924 = 17875^2 + 17382^2 .

It is a cyclic number.

It is not a de Polignac number, because 621649549 - 2¹⁷ = 621518477 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 621649499 and 621649508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621649529) 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, 54612 + ... + 65005.

It is an arithmetic number, because the mean of its divisors is an integer number (155443591).

Almost surely, 2^621649549 is an apocalyptic number.

It is an amenable number.

621649549 is a deficient number, since it is larger than the sum of its proper divisors (124815).

621649549 is a wasteful number, since it uses less digits than its factorization.

621649549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124814.

The product of its digits is 466560, while the sum is 46.

The square root of 621649549 is about 24932.9009343077. The cubic root of 621649549 is about 853.4574510047.

The spelling of 621649549 in words is "six hundred twenty-one million, six hundred forty-nine thousand, five hundred forty-nine".