261264637 has 2 divisors, whose sum is σ = 261264638. Its totient is φ = 261264636.

The previous prime is 261264623. The next prime is 261264643. The reversal of 261264637 is 736462162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 255168676 + 6095961 = 15974^2 + 2469^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261264637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261264596 and 261264605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261264667) 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 as a sum of consecutive naturals, namely, 130632318 + 130632319.

It is an arithmetic number, because the mean of its divisors is an integer number (130632319).

Almost surely, 2^261264637 is an apocalyptic number.

It is an amenable number.

261264637 is a deficient number, since it is larger than the sum of its proper divisors (1).

261264637 is an equidigital number, since it uses as much as digits as its factorization.

261264637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 37.

The square root of 261264637 is about 16163.6826558801. The cubic root of 261264637 is about 639.2835708724.

The spelling of 261264637 in words is "two hundred sixty-one million, two hundred sixty-four thousand, six hundred thirty-seven".