261813026 has 4 divisors (see below), whose sum is σ = 392719542. Its totient is φ = 130906512.

The previous prime is 261813023. The next prime is 261813047. The reversal of 261813026 is 620318162.

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., 216237025 + 45576001 = 14705^2 + 6751^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 261813026.

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 as a sum of consecutive naturals, namely, 65453255 + ... + 65453258.

Almost surely, 2^261813026 is an apocalyptic number.

261813026 is a deficient number, since it is larger than the sum of its proper divisors (130906516).

261813026 is a wasteful number, since it uses less digits than its factorization.

261813026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130906515.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 261813026 is about 16180.6373792876. The cubic root of 261813026 is about 639.7305392335.

The spelling of 261813026 in words is "two hundred sixty-one million, eight hundred thirteen thousand, twenty-six".