621554861 has 2 divisors, whose sum is σ = 621554862. Its totient is φ = 621554860.

The previous prime is 621554851. The next prime is 621554863. The reversal of 621554861 is 168455126.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 621554761 + 100 = 24931^2 + 10^2 .

It is a cyclic number.

It is not a de Polignac number, because 621554861 - 2¹⁰ = 621553837 is a prime.

Together with 621554863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621554863) 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, 310777430 + 310777431.

It is an arithmetic number, because the mean of its divisors is an integer number (310777431).

Almost surely, 2^621554861 is an apocalyptic number.

It is an amenable number.

621554861 is a deficient number, since it is larger than the sum of its proper divisors (1).

621554861 is an equidigital number, since it uses as much as digits as its factorization.

621554861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57600, while the sum is 38.

The square root of 621554861 is about 24931.0020055352. The cubic root of 621554861 is about 853.4141166842.

The spelling of 621554861 in words is "six hundred twenty-one million, five hundred fifty-four thousand, eight hundred sixty-one".