123778261 has 2 divisors, whose sum is σ = 123778262. Its totient is φ = 123778260.

The previous prime is 123778253. The next prime is 123778273. The reversal of 123778261 is 162877321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116856100 + 6922161 = 10810^2 + 2631^2 .

It is a cyclic number.

It is not a de Polignac number, because 123778261 - 2³ = 123778253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 123778261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123778201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61889130 + 61889131.

It is an arithmetic number, because the mean of its divisors is an integer number (61889131).

Almost surely, 2^123778261 is an apocalyptic number.

It is an amenable number.

123778261 is a deficient number, since it is larger than the sum of its proper divisors (1).

123778261 is an equidigital number, since it uses as much as digits as its factorization.

123778261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 37.

The square root of 123778261 is about 11125.5678956177. The cubic root of 123778261 is about 498.3656784733.

The spelling of 123778261 in words is "one hundred twenty-three million, seven hundred seventy-eight thousand, two hundred sixty-one".