261970321 has 2 divisors, whose sum is σ = 261970322. Its totient is φ = 261970320.

The previous prime is 261970307. The next prime is 261970337. The reversal of 261970321 is 123079162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 235960321 + 26010000 = 15361^2 + 5100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261970321 is a prime.

It is equal to p_14297611 and since 261970321 and 14297611 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (261970721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130985160 + 130985161.

It is an arithmetic number, because the mean of its divisors is an integer number (130985161).

Almost surely, 2^261970321 is an apocalyptic number.

It is an amenable number.

261970321 is a deficient number, since it is larger than the sum of its proper divisors (1).

261970321 is an equidigital number, since it uses as much as digits as its factorization.

261970321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 261970321 is about 16185.4972429024. The cubic root of 261970321 is about 639.8586284423.

The spelling of 261970321 in words is "two hundred sixty-one million, nine hundred seventy thousand, three hundred twenty-one".