261311653 has 4 divisors (see below), whose sum is σ = 261481900. Its totient is φ = 261141408.

The previous prime is 261311629. The next prime is 261311683. The reversal of 261311653 is 356113162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 141562404 + 119749249 = 11898^2 + 10943^2 .

It is a cyclic number.

It is not a de Polignac number, because 261311653 - 2⁵ = 261311621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261311683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82800 + ... + 85897.

It is an arithmetic number, because the mean of its divisors is an integer number (65370475).

Almost surely, 2^261311653 is an apocalyptic number.

It is an amenable number.

261311653 is a deficient number, since it is larger than the sum of its proper divisors (170247).

261311653 is a wasteful number, since it uses less digits than its factorization.

261311653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170246.

The product of its digits is 3240, while the sum is 28.

The square root of 261311653 is about 16165.1369619932. The cubic root of 261311653 is about 639.3219160970.

The spelling of 261311653 in words is "two hundred sixty-one million, three hundred eleven thousand, six hundred fifty-three".