549263781621 has 40 divisors (see below), whose sum is σ = 870438806424. Its totient is φ = 343974159360.

The previous prime is 549263781613. The next prime is 549263781623. The reversal of 549263781621 is 126187362945.

It is a happy number.

549263781621 is a `hidden beast` number, since 5 + 4 + 9 + 2 + 6 + 3 + 7 + 8 + 1 + 621 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 221312852721 + 327950928900 = 470439^2 + 572670^2 .

It is not a de Polignac number, because 549263781621 - 2³ = 549263781613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (549263781623) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 334611 + ... + 1100223.

Almost surely, 2^549263781621 is an apocalyptic number.

549263781621 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

549263781621 is a deficient number, since it is larger than the sum of its proper divisors (321175024803).

549263781621 is a wasteful number, since it uses less digits than its factorization.

549263781621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 766163 (or 766154 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The spelling of 549263781621 in words is "five hundred forty-nine billion, two hundred sixty-three million, seven hundred eighty-one thousand, six hundred twenty-one".