261364813 has 4 divisors (see below), whose sum is σ = 269795968. Its totient is φ = 252933660.

The previous prime is 261364777. The next prime is 261364841. The reversal of 261364813 is 318463162.

It is a happy number.

261364813 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 318463162 = 2 ⋅159231581.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261364813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261368813) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4215531 + ... + 4215592.

It is an arithmetic number, because the mean of its divisors is an integer number (67448992).

Almost surely, 2^261364813 is an apocalyptic number.

It is an amenable number.

261364813 is a deficient number, since it is larger than the sum of its proper divisors (8431155).

261364813 is an equidigital number, since it uses as much as digits as its factorization.

261364813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8431154.

The product of its digits is 20736, while the sum is 34.

The square root of 261364813 is about 16166.7811576702. The cubic root of 261364813 is about 639.3652666943.

The spelling of 261364813 in words is "two hundred sixty-one million, three hundred sixty-four thousand, eight hundred thirteen".