65640331 has 16 divisors (see below), whose sum is σ = 69360640. Its totient is φ = 62052480.

The previous prime is 65640319. The next prime is 65640343. The reversal of 65640331 is 13304656.

It is an interprime number because it is at equal distance from previous prime (65640319) and next prime (65640343).

It is a cyclic number.

It is not a de Polignac number, because 65640331 - 2¹⁷ = 65509259 is a prime.

It is a super-2 number, since 2×65640331² = 8617306107579122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65640331.

It is not an unprimeable number, because it can be changed into a prime (65640431) 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, 286525 + ... + 286753.

It is an arithmetic number, because the mean of its divisors is an integer number (4335040).

Almost surely, 2^65640331 is an apocalyptic number.

65640331 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

65640331 is a deficient number, since it is larger than the sum of its proper divisors (3720309).

65640331 is a wasteful number, since it uses less digits than its factorization.

65640331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454.

The product of its (nonzero) digits is 6480, while the sum is 28.

The square root of 65640331 is about 8101.8720676150. The cubic root of 65640331 is about 403.3885691869.

Adding to 65640331 its reverse (13304656), we get a palindrome (78944987).

The spelling of 65640331 in words is "sixty-five million, six hundred forty thousand, three hundred thirty-one".