621790861 has 4 divisors (see below), whose sum is σ = 658366812. Its totient is φ = 585214912.

The previous prime is 621790847. The next prime is 621790867. The reversal of 621790861 is 168097126.

621790861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 431185225 + 190605636 = 20765^2 + 13806^2 .

It is a cyclic number.

It is not a de Polignac number, because 621790861 - 2⁷ = 621790733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621790867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18287950 + ... + 18287983.

It is an arithmetic number, because the mean of its divisors is an integer number (164591703).

Almost surely, 2^621790861 is an apocalyptic number.

It is an amenable number.

621790861 is a deficient number, since it is larger than the sum of its proper divisors (36575951).

621790861 is a wasteful number, since it uses less digits than its factorization.

621790861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36575950.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 621790861 is about 24935.7346192167. The cubic root of 621790861 is about 853.5221147917.

The spelling of 621790861 in words is "six hundred twenty-one million, seven hundred ninety thousand, eight hundred sixty-one".