621684827549 has 2 divisors, whose sum is σ = 621684827550. Its totient is φ = 621684827548.

The previous prime is 621684827537. The next prime is 621684827629. The reversal of 621684827549 is 945728486126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 457947251524 + 163737576025 = 676718^2 + 404645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621684827549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 621684827491 and 621684827500.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621684827749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310842413774 + 310842413775.

It is an arithmetic number, because the mean of its divisors is an integer number (310842413775).

Almost surely, 2^621684827549 is an apocalyptic number.

It is an amenable number.

621684827549 is a deficient number, since it is larger than the sum of its proper divisors (1).

621684827549 is an equidigital number, since it uses as much as digits as its factorization.

621684827549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46448640, while the sum is 62.

The spelling of 621684827549 in words is "six hundred twenty-one billion, six hundred eighty-four million, eight hundred twenty-seven thousand, five hundred forty-nine".