621816780073 has 4 divisors (see below), whose sum is σ = 621821829060. Its totient is φ = 621811731088.

The previous prime is 621816780029. The next prime is 621816780097. The reversal of 621816780073 is 370087618126.

It is a happy number.

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 223853889424 + 397962890649 = 473132^2 + 630843^2 .

It is a cyclic number.

It is not a de Polignac number, because 621816780073 - 2¹³ = 621816771881 is a prime.

It is a super-2 number, since 2×621816780073² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 621816779999 and 621816780026.

It is not an unprimeable number, because it can be changed into a prime (621816780973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2335018 + ... + 2587651.

It is an arithmetic number, because the mean of its divisors is an integer number (155455457265).

Almost surely, 2^621816780073 is an apocalyptic number.

It is an amenable number.

621816780073 is a deficient number, since it is larger than the sum of its proper divisors (5048987).

621816780073 is a wasteful number, since it uses less digits than its factorization.

621816780073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5048986.

The product of its (nonzero) digits is 677376, while the sum is 49.

The spelling of 621816780073 in words is "six hundred twenty-one billion, eight hundred sixteen million, seven hundred eighty thousand, seventy-three".