65640605 has 8 divisors (see below), whose sum is σ = 78891864. Its totient is φ = 52430400.

The previous prime is 65640599. The next prime is 65640629. The reversal of 65640605 is 50604656.

It can be written as a sum of positive squares in 4 ways, for example, as 1304164 + 64336441 = 1142^2 + 8021^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65640605 - 2¹⁸ = 65378461 is a prime.

It is a super-3 number, since 3×65640605³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6626 + ... + 13235.

It is an arithmetic number, because the mean of its divisors is an integer number (9861483).

Almost surely, 2^65640605 is an apocalyptic number.

It is an amenable number.

65640605 is a deficient number, since it is larger than the sum of its proper divisors (13251259).

65640605 is a wasteful number, since it uses less digits than its factorization.

65640605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20527.

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 65640605 is about 8101.8889772694. Note that the first 3 decimals coincide. The cubic root of 65640605 is about 403.3891304695.

The spelling of 65640605 in words is "sixty-five million, six hundred forty thousand, six hundred five".