65656981 has 8 divisors (see below), whose sum is σ = 72619064. Its totient is φ = 58968000.

The previous prime is 65656963. The next prime is 65657017. The reversal of 65656981 is 18965656.

It can be written as a sum of positive squares in 4 ways, for example, as 3783025 + 61873956 = 1945^2 + 7866^2 .

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

It is not a de Polignac number, because 65656981 - 2¹³ = 65648789 is a prime.

It is a super-2 number, since 2×65656981² = 8621678308068722, which contains 22 as substring.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65656961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67770 + ... + 68731.

It is an arithmetic number, because the mean of its divisors is an integer number (9077383).

Almost surely, 2^65656981 is an apocalyptic number.

It is an amenable number.

65656981 is a deficient number, since it is larger than the sum of its proper divisors (6962083).

65656981 is a wasteful number, since it uses less digits than its factorization.

65656981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136551.

The product of its digits is 388800, while the sum is 46.

The square root of 65656981 is about 8102.8995427563. The cubic root of 65656981 is about 403.4226734831.

The spelling of 65656981 in words is "sixty-five million, six hundred fifty-six thousand, nine hundred eighty-one".