261520436 has 6 divisors (see below), whose sum is σ = 457660770. Its totient is φ = 130760216.

The previous prime is 261520423. The next prime is 261520451. The reversal of 261520436 is 634025162.

It can be written as a sum of positive squares in only one way, i.e., 261016336 + 504100 = 16156^2 + 710^2 .

It is a junction number, because it is equal to n+sod(n) for n = 261520399 and 261520408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32690051 + ... + 32690058.

It is an arithmetic number, because the mean of its divisors is an integer number (76276795).

Almost surely, 2^261520436 is an apocalyptic number.

It is an amenable number.

261520436 is a deficient number, since it is larger than the sum of its proper divisors (196140334).

261520436 is a wasteful number, since it uses less digits than its factorization.

261520436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65380113 (or 65380111 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 261520436 is about 16171.5934898204. The cubic root of 261520436 is about 639.4921394206.

Adding to 261520436 its reverse (634025162), we get a palindrome (895545598).

The spelling of 261520436 in words is "two hundred sixty-one million, five hundred twenty thousand, four hundred thirty-six".