261021 has 8 divisors (see below), whose sum is σ = 350784. Its totient is φ = 172640.

The previous prime is 261017. The next prime is 261031. The reversal of 261021 is 120162.

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

It is a cyclic number.

It is not a de Polignac number, because 261021 - 2² = 261017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 260988 and 261006.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261021.

It is not an unprimeable number, because it can be changed into a prime (261011) 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, 241 + ... + 761.

It is an arithmetic number, because the mean of its divisors is an integer number (43848).

2²⁶¹⁰²¹ is an apocalyptic number.

It is an amenable number.

261021 is a deficient number, since it is larger than the sum of its proper divisors (89763).

261021 is a wasteful number, since it uses less digits than its factorization.

261021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 261021 is about 510.9021432721. The cubic root of 261021 is about 63.9084792126.

Adding to 261021 its reverse (120162), we get a palindrome (381183).

The spelling of 261021 in words is "two hundred sixty-one thousand, twenty-one".