261124021 has 4 divisors (see below), whose sum is σ = 262117152. Its totient is φ = 260130892.

The previous prime is 261124009. The next prime is 261124081. The reversal of 261124021 is 120421162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261124021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261124021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261124001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496171 + ... + 496696.

It is an arithmetic number, because the mean of its divisors is an integer number (65529288).

Almost surely, 2^261124021 is an apocalyptic number.

It is an amenable number.

261124021 is a deficient number, since it is larger than the sum of its proper divisors (993131).

261124021 is an equidigital number, since it uses as much as digits as its factorization.

261124021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993130.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 261124021 is about 16159.3323191275. The cubic root of 261124021 is about 639.1688600671.

Adding to 261124021 its reverse (120421162), we get a palindrome (381545183).

The spelling of 261124021 in words is "two hundred sixty-one million, one hundred twenty-four thousand, twenty-one".