261335025 has 192 divisors, whose sum is σ = 599961600. Its totient is φ = 108864000.

The previous prime is 261335023. The next prime is 261335027. The reversal of 261335025 is 520533162.

261335025 is a `hidden beast` number, since 26 + 133 + 502 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (261335023) and next prime (261335027).

Together with 338626574 it forms a betrothed pair.

It is not a de Polignac number, because 261335025 - 2¹ = 261335023 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 261335025.

It is not an unprimeable number, because it can be changed into a prime (261335023) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3680740 + ... + 3680810.

It is an arithmetic number, because the mean of its divisors is an integer number (3124800).

Almost surely, 2^261335025 is an apocalyptic number.

261335025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261335025 is an abundant number, since it is smaller than the sum of its proper divisors (338626575).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261335025 is a wasteful number, since it uses less digits than its factorization.

261335025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

The square root of 261335025 is about 16165.8598595930. The cubic root of 261335025 is about 639.3409760792.

Adding to 261335025 its reverse (520533162), we get a palindrome (781868187).

The spelling of 261335025 in words is "two hundred sixty-one million, three hundred thirty-five thousand, twenty-five".