261999077 has 2 divisors, whose sum is σ = 261999078. Its totient is φ = 261999076.

The previous prime is 261999047. The next prime is 261999091. The reversal of 261999077 is 770999162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220641316 + 41357761 = 14854^2 + 6431^2 .

It is a cyclic number.

It is not a de Polignac number, because 261999077 - 2¹⁶ = 261933541 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261999007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130999538 + 130999539.

It is an arithmetic number, because the mean of its divisors is an integer number (130999539).

Almost surely, 2^261999077 is an apocalyptic number.

It is an amenable number.

261999077 is a deficient number, since it is larger than the sum of its proper divisors (1).

261999077 is an equidigital number, since it uses as much as digits as its factorization.

261999077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 428652, while the sum is 50.

The square root of 261999077 is about 16186.3855446483. The cubic root of 261999077 is about 639.8820396204.

The spelling of 261999077 in words is "two hundred sixty-one million, nine hundred ninety-nine thousand, seventy-seven".