78265261 has 2 divisors, whose sum is σ = 78265262. Its totient is φ = 78265260.

The previous prime is 78265241. The next prime is 78265301. The reversal of 78265261 is 16256287.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44555625 + 33709636 = 6675^2 + 5806^2 .

It is an emirp because it is prime and its reverse (16256287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78265261 - 2¹⁵ = 78232493 is a prime.

It is a super-2 number, since 2×78265261² = 12250902158796242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78265261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78265241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39132630 + 39132631.

It is an arithmetic number, because the mean of its divisors is an integer number (39132631).

Almost surely, 2^78265261 is an apocalyptic number.

It is an amenable number.

78265261 is a deficient number, since it is larger than the sum of its proper divisors (1).

78265261 is an equidigital number, since it uses as much as digits as its factorization.

78265261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 37.

The square root of 78265261 is about 8846.7655671437. The cubic root of 78265261 is about 427.7496661849.

The spelling of 78265261 in words is "seventy-eight million, two hundred sixty-five thousand, two hundred sixty-one".