261925290 has 192 divisors, whose sum is σ = 800616960. Its totient is φ = 58705920.

The previous prime is 261925289. The next prime is 261925297. The reversal of 261925290 is 92529162.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (261925297) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1329472 + ... + 1329668.

It is an arithmetic number, because the mean of its divisors is an integer number (4169880).

Almost surely, 2^261925290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261925290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (400308480).

261925290 is an abundant number, since it is smaller than the sum of its proper divisors (538691670).

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

261925290 is a wasteful number, since it uses less digits than its factorization.

261925290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 261925290 is about 16184.1060920892. The cubic root of 261925290 is about 639.8219638246.

The spelling of 261925290 in words is "two hundred sixty-one million, nine hundred twenty-five thousand, two hundred ninety".