261099649 has 2 divisors, whose sum is σ = 261099650. Its totient is φ = 261099648.

The previous prime is 261099599. The next prime is 261099659. The reversal of 261099649 is 946990162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259049025 + 2050624 = 16095^2 + 1432^2 .

It is a cyclic number.

It is not a de Polignac number, because 261099649 - 2¹⁷ = 260968577 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261099599 and 261099608.

It is not a weakly prime, because it can be changed into another prime (261099659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130549824 + 130549825.

It is an arithmetic number, because the mean of its divisors is an integer number (130549825).

Almost surely, 2^261099649 is an apocalyptic number.

It is an amenable number.

261099649 is a deficient number, since it is larger than the sum of its proper divisors (1).

261099649 is an equidigital number, since it uses as much as digits as its factorization.

261099649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 261099649 is about 16158.5781862143. The cubic root of 261099649 is about 639.1489738484.

The spelling of 261099649 in words is "two hundred sixty-one million, ninety-nine thousand, six hundred forty-nine".