261405015 has 16 divisors (see below), whose sum is σ = 422949600. Its totient is φ = 137848832.

The previous prime is 261404993. The next prime is 261405049. The reversal of 261405015 is 510504162.

It is a cyclic number.

It is not a de Polignac number, because 261405015 - 2⁶ = 261404951 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96570 + ... + 99239.

It is an arithmetic number, because the mean of its divisors is an integer number (26434350).

Almost surely, 2^261405015 is an apocalyptic number.

261405015 is a deficient number, since it is larger than the sum of its proper divisors (161544585).

261405015 is a wasteful number, since it uses less digits than its factorization.

261405015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195906.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 261405015 is about 16168.0244618815. The cubic root of 261405015 is about 639.3980464761.

Adding to 261405015 its reverse (510504162), we get a palindrome (771909177).

It can be divided in two parts, 26 and 1405015, that added together give a palindrome (1405041).

The spelling of 261405015 in words is "two hundred sixty-one million, four hundred five thousand, fifteen".