261813025 has 24 divisors (see below), whose sum is σ = 346674240. Its totient is φ = 195666240.

The previous prime is 261813023. The next prime is 261813047. The reversal of 261813025 is 520318162.

It is not a de Polignac number, because 261813025 - 2¹ = 261813023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261812984 and 261813002.

It is not an unprimeable number, because it can be changed into a prime (261813023) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19431 + ... + 30019.

It is an arithmetic number, because the mean of its divisors is an integer number (14444760).

Almost surely, 2^261813025 is an apocalyptic number.

261813025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261813025 is a deficient number, since it is larger than the sum of its proper divisors (84861215).

261813025 is a wasteful number, since it uses less digits than its factorization.

261813025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10665 (or 10660 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 261813025 is about 16180.6373483865. The cubic root of 261813025 is about 639.7305384190.

The spelling of 261813025 in words is "two hundred sixty-one million, eight hundred thirteen thousand, twenty-five".