65250781 has 2 divisors, whose sum is σ = 65250782. Its totient is φ = 65250780.

The previous prime is 65250767. The next prime is 65250851. The reversal of 65250781 is 18705256.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57912100 + 7338681 = 7610^2 + 2709^2 .

It is a cyclic number.

It is not a de Polignac number, because 65250781 - 2⁵ = 65250749 is a prime.

It is a super-2 number, since 2×65250781² = 8515328842219922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65250751) 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, 32625390 + 32625391.

It is an arithmetic number, because the mean of its divisors is an integer number (32625391).

Almost surely, 2^65250781 is an apocalyptic number.

65250781 is the 3613-rd centered decagonal number.

It is an amenable number.

65250781 is a deficient number, since it is larger than the sum of its proper divisors (1).

65250781 is an equidigital number, since it uses as much as digits as its factorization.

65250781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 65250781 is about 8077.7955532435. The cubic root of 65250781 is about 402.5890002899.

The spelling of 65250781 in words is "sixty-five million, two hundred fifty thousand, seven hundred eighty-one".