261461021 has 4 divisors (see below), whose sum is σ = 262100700. Its totient is φ = 260821344.

The previous prime is 261461017. The next prime is 261461063. The reversal of 261461021 is 120164162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120164162 = 2 ⋅60082081.

It can be written as a sum of positive squares in 2 ways, for example, as 190716100 + 70744921 = 13810^2 + 8411^2 .

It is a cyclic number.

It is not a de Polignac number, because 261461021 - 2² = 261461017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261461521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 319226 + ... + 320043.

It is an arithmetic number, because the mean of its divisors is an integer number (65525175).

Almost surely, 2^261461021 is an apocalyptic number.

It is an amenable number.

261461021 is a deficient number, since it is larger than the sum of its proper divisors (639679).

261461021 is an equidigital number, since it uses as much as digits as its factorization.

261461021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639678.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 261461021 is about 16169.7563679853. The cubic root of 261461021 is about 639.4437068726.

The spelling of 261461021 in words is "two hundred sixty-one million, four hundred sixty-one thousand, twenty-one".