261639213 has 8 divisors (see below), whose sum is σ = 380566176. Its totient is φ = 158569200.

The previous prime is 261639211. The next prime is 261639269. The reversal of 261639213 is 312936162.

261639213 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261639213 - 2¹ = 261639211 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 7928461 = 261639213 / (2 + 6 + 1 + 6 + 3 + 9 + 2 + 1 + 3).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261639211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3964198 + ... + 3964263.

It is an arithmetic number, because the mean of its divisors is an integer number (47570772).

Almost surely, 2^261639213 is an apocalyptic number.

It is an amenable number.

261639213 is a deficient number, since it is larger than the sum of its proper divisors (118926963).

261639213 is a wasteful number, since it uses less digits than its factorization.

261639213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7928475.

The product of its digits is 11664, while the sum is 33.

The square root of 261639213 is about 16175.2654692280. The cubic root of 261639213 is about 639.5889393273.

The spelling of 261639213 in words is "two hundred sixty-one million, six hundred thirty-nine thousand, two hundred thirteen".