261670421 has 2 divisors, whose sum is σ = 261670422. Its totient is φ = 261670420.

The previous prime is 261670403. The next prime is 261670439. The reversal of 261670421 is 124076162.

261670421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (261670403) and next prime (261670439).

It can be written as a sum of positive squares in only one way, i.e., 254753521 + 6916900 = 15961^2 + 2630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261670421 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 (261670441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130835210 + 130835211.

It is an arithmetic number, because the mean of its divisors is an integer number (130835211).

Almost surely, 2^261670421 is an apocalyptic number.

It is an amenable number.

261670421 is a deficient number, since it is larger than the sum of its proper divisors (1).

261670421 is an equidigital number, since it uses as much as digits as its factorization.

261670421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 261670421 is about 16176.2301232395. The cubic root of 261670421 is about 639.6143681074.

It can be divided in two parts, 2616 and 70421, that added together give a palindrome (73037).

The spelling of 261670421 in words is "two hundred sixty-one million, six hundred seventy thousand, four hundred twenty-one".