261663394 has 8 divisors (see below), whose sum is σ = 402068268. Its totient is φ = 127640640.

The previous prime is 261663379. The next prime is 261663397. The reversal of 261663394 is 493366162.

261663394 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 211324369 + 50339025 = 14537^2 + 7095^2 .

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

It is not an unprimeable number, because it can be changed into a prime (261663397) 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, 1595427 + ... + 1595590.

Almost surely, 2^261663394 is an apocalyptic number.

261663394 is a deficient number, since it is larger than the sum of its proper divisors (140404874).

261663394 is a wasteful number, since it uses less digits than its factorization.

261663394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3191060.

The product of its digits is 139968, while the sum is 40.

The square root of 261663394 is about 16176.0129203707. The cubic root of 261663394 is about 639.6086425712.

The spelling of 261663394 in words is "two hundred sixty-one million, six hundred sixty-three thousand, three hundred ninety-four".