261417921 has 8 divisors (see below), whose sum is σ = 350364000. Its totient is φ = 173375232.

The previous prime is 261417917. The next prime is 261417971. The reversal of 261417921 is 129714162.

It is a happy number.

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

It is not a de Polignac number, because 261417921 - 2² = 261417917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261417911) 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, 225171 + ... + 226328.

It is an arithmetic number, because the mean of its divisors is an integer number (43795500).

Almost surely, 2^261417921 is an apocalyptic number.

It is an amenable number.

261417921 is a deficient number, since it is larger than the sum of its proper divisors (88946079).

261417921 is a wasteful number, since it uses less digits than its factorization.

261417921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451695.

The product of its digits is 6048, while the sum is 33.

The square root of 261417921 is about 16168.4235780734. The cubic root of 261417921 is about 639.4085690177.

The spelling of 261417921 in words is "two hundred sixty-one million, four hundred seventeen thousand, nine hundred twenty-one".