261636026 has 4 divisors (see below), whose sum is σ = 392454042. Its totient is φ = 130818012.

The previous prime is 261636013. The next prime is 261636029. The reversal of 261636026 is 620636162.

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., 254881225 + 6754801 = 15965^2 + 2599^2 .

It is a junction number, because it is equal to n+sod(n) for n = 261635983 and 261636001.

It is not an unprimeable number, because it can be changed into a prime (261636029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65409005 + ... + 65409008.

Almost surely, 2^261636026 is an apocalyptic number.

261636026 is a deficient number, since it is larger than the sum of its proper divisors (130818016).

261636026 is a wasteful number, since it uses less digits than its factorization.

261636026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130818015.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 261636026 is about 16175.1669543161. The cubic root of 261636026 is about 639.5863423947.

The spelling of 261636026 in words is "two hundred sixty-one million, six hundred thirty-six thousand, twenty-six".