623809861 has 2 divisors, whose sum is σ = 623809862. Its totient is φ = 623809860.

The previous prime is 623809831. The next prime is 623809867. The reversal of 623809861 is 168908326.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 596873761 + 26936100 = 24431^2 + 5190^2 .

It is a cyclic number.

It is not a de Polignac number, because 623809861 - 2⁷ = 623809733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (623809867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311904930 + 311904931.

It is an arithmetic number, because the mean of its divisors is an integer number (311904931).

Almost surely, 2^623809861 is an apocalyptic number.

It is an amenable number.

623809861 is a deficient number, since it is larger than the sum of its proper divisors (1).

623809861 is an equidigital number, since it uses as much as digits as its factorization.

623809861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 623809861 is about 24976.1858777516. The cubic root of 623809861 is about 854.4449327521. Note that the first 3 decimals are identical.

The spelling of 623809861 in words is "six hundred twenty-three million, eight hundred nine thousand, eight hundred sixty-one".