261555449 has 2 divisors, whose sum is σ = 261555450. Its totient is φ = 261555448.

The previous prime is 261555403. The next prime is 261555457. The reversal of 261555449 is 944555162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256000000 + 5555449 = 16000^2 + 2357^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261555449 is a prime.

It is a super-2 number, since 2×261555449² = 136822505803183202, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261555499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130777724 + 130777725.

It is an arithmetic number, because the mean of its divisors is an integer number (130777725).

Almost surely, 2^261555449 is an apocalyptic number.

It is an amenable number.

261555449 is a deficient number, since it is larger than the sum of its proper divisors (1).

261555449 is an equidigital number, since it uses as much as digits as its factorization.

261555449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216000, while the sum is 41.

The square root of 261555449 is about 16172.6759999698. The cubic root of 261555449 is about 639.5206770746.

The spelling of 261555449 in words is "two hundred sixty-one million, five hundred fifty-five thousand, four hundred forty-nine".