261540418 has 4 divisors (see below), whose sum is σ = 392310630. Its totient is φ = 130770208.

The previous prime is 261540413. The next prime is 261540439. The reversal of 261540418 is 814045162.

261540418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 237067609 + 24472809 = 15397^2 + 4947^2 .

It is a super-2 number, since 2×261540418² = 136806780495229448, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 261540418.

It is not an unprimeable number, because it can be changed into a prime (261540413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65385103 + ... + 65385106.

Almost surely, 2^261540418 is an apocalyptic number.

261540418 is a deficient number, since it is larger than the sum of its proper divisors (130770212).

261540418 is a wasteful number, since it uses less digits than its factorization.

261540418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130770211.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 261540418 is about 16172.2112897402. The cubic root of 261540418 is about 639.5084262377.

The spelling of 261540418 in words is "two hundred sixty-one million, five hundred forty thousand, four hundred eighteen".