261861826 has 4 divisors (see below), whose sum is σ = 392792742. Its totient is φ = 130930912.

The previous prime is 261861823. The next prime is 261861827. The reversal of 261861826 is 628168162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 243328801 + 18533025 = 15599^2 + 4305^2 .

It is not an unprimeable number, because it can be changed into a prime (261861823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65465455 + ... + 65465458.

Almost surely, 2^261861826 is an apocalyptic number.

261861826 is a deficient number, since it is larger than the sum of its proper divisors (130930916).

261861826 is a wasteful number, since it uses less digits than its factorization.

261861826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130930915.

The product of its digits is 55296, while the sum is 40.

The square root of 261861826 is about 16182.1452842322. The cubic root of 261861826 is about 639.7702837684.

The spelling of 261861826 in words is "two hundred sixty-one million, eight hundred sixty-one thousand, eight hundred twenty-six".