261213745 has 16 divisors (see below), whose sum is σ = 338384592. Its totient is φ = 192430080.

The previous prime is 261213697. The next prime is 261213749. The reversal of 261213745 is 547312162.

It can be written as a sum of positive squares in 8 ways, for example, as 17572864 + 243640881 = 4192^2 + 15609^2 .

It is a de Polignac number, because none of the positive numbers 2^k-261213745 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261213749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23505 + ... + 32785.

It is an arithmetic number, because the mean of its divisors is an integer number (21149037).

Almost surely, 2^261213745 is an apocalyptic number.

It is an amenable number.

261213745 is a deficient number, since it is larger than the sum of its proper divisors (77170847).

261213745 is a wasteful number, since it uses less digits than its factorization.

261213745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9732.

The product of its digits is 10080, while the sum is 31.

The square root of 261213745 is about 16162.1083092522. The cubic root of 261213745 is about 639.2420592815.

The spelling of 261213745 in words is "two hundred sixty-one million, two hundred thirteen thousand, seven hundred forty-five".