261876421 has 2 divisors, whose sum is σ = 261876422. Its totient is φ = 261876420.

The previous prime is 261876403. The next prime is 261876443. The reversal of 261876421 is 124678162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160149025 + 101727396 = 12655^2 + 10086^2 .

It is a cyclic number.

It is not a de Polignac number, because 261876421 - 2⁹ = 261875909 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261876481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130938210 + 130938211.

It is an arithmetic number, because the mean of its divisors is an integer number (130938211).

Almost surely, 2^261876421 is an apocalyptic number.

It is an amenable number.

261876421 is a deficient number, since it is larger than the sum of its proper divisors (1).

261876421 is an equidigital number, since it uses as much as digits as its factorization.

261876421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 37.

The square root of 261876421 is about 16182.5962379341. The cubic root of 261876421 is about 639.7821695199.

The spelling of 261876421 in words is "two hundred sixty-one million, eight hundred seventy-six thousand, four hundred twenty-one".