621724813 has 2 divisors, whose sum is σ = 621724814. Its totient is φ = 621724812.

The previous prime is 621724787. The next prime is 621724849. The reversal of 621724813 is 318427126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619910404 + 1814409 = 24898^2 + 1347^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621724813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621724853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310862406 + 310862407.

It is an arithmetic number, because the mean of its divisors is an integer number (310862407).

Almost surely, 2^621724813 is an apocalyptic number.

It is an amenable number.

621724813 is a deficient number, since it is larger than the sum of its proper divisors (1).

621724813 is an equidigital number, since it uses as much as digits as its factorization.

621724813 is an odious number, because the sum of its binary digits is odd.

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

The square root of 621724813 is about 24934.4102196142. The cubic root of 621724813 is about 853.4918927195.

The spelling of 621724813 in words is "six hundred twenty-one million, seven hundred twenty-four thousand, eight hundred thirteen".