209123965837 has 2 divisors, whose sum is σ = 209123965838. Its totient is φ = 209123965836.

The previous prime is 209123965819. The next prime is 209123965867. The reversal of 209123965837 is 738569321902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 146072253636 + 63051712201 = 382194^2 + 251101^2 .

It is a cyclic number.

It is not a de Polignac number, because 209123965837 - 2³¹ = 206976482189 is a prime.

It is a super-2 number, since 2×209123965837² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209123965867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104561982918 + 104561982919.

It is an arithmetic number, because the mean of its divisors is an integer number (104561982919).

Almost surely, 2^209123965837 is an apocalyptic number.

It is an amenable number.

209123965837 is a deficient number, since it is larger than the sum of its proper divisors (1).

209123965837 is an equidigital number, since it uses as much as digits as its factorization.

209123965837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4898880, while the sum is 55.

The spelling of 209123965837 in words is "two hundred nine billion, one hundred twenty-three million, nine hundred sixty-five thousand, eight hundred thirty-seven".