261994394 has 4 divisors (see below), whose sum is σ = 392991594. Its totient is φ = 130997196.

The previous prime is 261994393. The next prime is 261994409. The reversal of 261994394 is 493499162.

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., 202009369 + 59985025 = 14213^2 + 7745^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261994393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65498597 + ... + 65498600.

Almost surely, 2^261994394 is an apocalyptic number.

261994394 is a deficient number, since it is larger than the sum of its proper divisors (130997200).

261994394 is a wasteful number, since it uses less digits than its factorization.

261994394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130997199.

The product of its digits is 419904, while the sum is 47.

The square root of 261994394 is about 16186.2408853940. The cubic root of 261994394 is about 639.8782271573.

The spelling of 261994394 in words is "two hundred sixty-one million, nine hundred ninety-four thousand, three hundred ninety-four".