261768021 has 8 divisors (see below), whose sum is σ = 349101984. Its totient is φ = 174473040.

The previous prime is 261767971. The next prime is 261768049. The reversal of 261768021 is 120867162.

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

It is not a de Polignac number, because 261768021 - 2⁷ = 261767893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261768071) 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, 14655 + ... + 27171.

It is an arithmetic number, because the mean of its divisors is an integer number (43637748).

Almost surely, 2^261768021 is an apocalyptic number.

It is an amenable number.

261768021 is a deficient number, since it is larger than the sum of its proper divisors (87333963).

261768021 is a wasteful number, since it uses less digits than its factorization.

261768021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19491.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 261768021 is about 16179.2466141041. The cubic root of 261768021 is about 639.6938811099.

The spelling of 261768021 in words is "two hundred sixty-one million, seven hundred sixty-eight thousand, twenty-one".