65278509 has 16 divisors (see below), whose sum is σ = 91822080. Its totient is φ = 41137200.

The previous prime is 65278483. The next prime is 65278513. The reversal of 65278509 is 90587256.

It is not a de Polignac number, because 65278509 - 2⁹ = 65277997 is a prime.

It is a super-2 number, since 2×65278509² = 8522567474526162, 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 an unprimeable number, because it can be changed into a prime (65278579) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32484 + ... + 34434.

It is an arithmetic number, because the mean of its divisors is an integer number (5738880).

Almost surely, 2^65278509 is an apocalyptic number.

It is an amenable number.

65278509 is a deficient number, since it is larger than the sum of its proper divisors (26543571).

65278509 is a wasteful number, since it uses less digits than its factorization.

65278509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2560.

The product of its (nonzero) digits is 151200, while the sum is 42.

The square root of 65278509 is about 8079.5116807886. The cubic root of 65278509 is about 402.6460182891.

The spelling of 65278509 in words is "sixty-five million, two hundred seventy-eight thousand, five hundred nine".