261405513 has 12 divisors (see below), whose sum is σ = 378254448. Its totient is φ = 173961720.

The previous prime is 261405509. The next prime is 261405559. The reversal of 261405513 is 315504162.

261405513 is a `hidden beast` number, since 2 + 6 + 140 + 5 + 513 = 666.

It is not a de Polignac number, because 261405513 - 2² = 261405509 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261405713) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20295 + ... + 30572.

It is an arithmetic number, because the mean of its divisors is an integer number (31521204).

Almost surely, 2^261405513 is an apocalyptic number.

It is an amenable number.

261405513 is a deficient number, since it is larger than the sum of its proper divisors (116848935).

261405513 is a wasteful number, since it uses less digits than its factorization.

261405513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51444 (or 51441 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 261405513 is about 16168.0398626426. The cubic root of 261405513 is about 639.3984525127.

Adding to 261405513 its reverse (315504162), we get a palindrome (576909675).

The spelling of 261405513 in words is "two hundred sixty-one million, four hundred five thousand, five hundred thirteen".