261505604 has 24 divisors (see below), whose sum is σ = 467230680. Its totient is φ = 128021504.

The previous prime is 261505583. The next prime is 261505609. The reversal of 261505604 is 406505162.

It can be written as a sum of positive squares in 4 ways, for example, as 31922500 + 229583104 = 5650^2 + 15152^2 .

It is not an unprimeable number, because it can be changed into a prime (261505609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137492 + ... + 139380.

It is an arithmetic number, because the mean of its divisors is an integer number (19467945).

Almost surely, 2^261505604 is an apocalyptic number.

It is an amenable number.

261505604 is a deficient number, since it is larger than the sum of its proper divisors (205725076).

261505604 is a wasteful number, since it uses less digits than its factorization.

261505604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2599 (or 2597 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 261505604 is about 16171.1349014223. The cubic root of 261505604 is about 639.4800497004.

The spelling of 261505604 in words is "two hundred sixty-one million, five hundred five thousand, six hundred four".