261322587 has 6 divisors (see below), whose sum is σ = 377465972. Its totient is φ = 174215052.

The previous prime is 261322583. The next prime is 261322603. The reversal of 261322587 is 785223162.

It is not a de Polignac number, because 261322587 - 2² = 261322583 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261322583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14517913 + ... + 14517930.

Almost surely, 2^261322587 is an apocalyptic number.

261322587 is a deficient number, since it is larger than the sum of its proper divisors (116143385).

261322587 is a wasteful number, since it uses less digits than its factorization.

261322587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29035849 (or 29035846 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 261322587 is about 16165.4751554045. The cubic root of 261322587 is about 639.3308329699.

It can be divided in two parts, 2613 and 22587, that added together give a triangular number (25200 = T₂₂₄).

The spelling of 261322587 in words is "two hundred sixty-one million, three hundred twenty-two thousand, five hundred eighty-seven".