65661401 has 6 divisors (see below), whose sum is σ = 71100990. Its totient is φ = 60610368.

The previous prime is 65661373. The next prime is 65661457. The reversal of 65661401 is 10416656.

It can be written as a sum of positive squares in 3 ways, for example, as 8265625 + 57395776 = 2875^2 + 7576^2 .

It is a de Polignac number, because none of the positive numbers 2^k-65661401 is a prime.

It is a super-2 number, since 2×65661401² = 8622839162565602, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65661461) 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 in 5 ways as a sum of consecutive naturals, for example, 194096 + ... + 194433.

It is an arithmetic number, because the mean of its divisors is an integer number (11850165).

Almost surely, 2^65661401 is an apocalyptic number.

It is an amenable number.

65661401 is a deficient number, since it is larger than the sum of its proper divisors (5439589).

65661401 is a wasteful number, since it uses less digits than its factorization.

65661401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388555 (or 388542 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 65661401 is about 8103.1722800395. The cubic root of 65661401 is about 403.4317260275.

The spelling of 65661401 in words is "sixty-five million, six hundred sixty-one thousand, four hundred one".