65661901 has 2 divisors, whose sum is σ = 65661902. Its totient is φ = 65661900.

The previous prime is 65661899. The next prime is 65661931. The reversal of 65661901 is 10916656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48860100 + 16801801 = 6990^2 + 4099^2 .

It is a cyclic number.

It is not a de Polignac number, because 65661901 - 2¹ = 65661899 is a prime.

It is a super-2 number, since 2×65661901² = 8622970485867602, which contains 22 as substring.

Together with 65661899, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65661931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32830950 + 32830951.

It is an arithmetic number, because the mean of its divisors is an integer number (32830951).

Almost surely, 2^65661901 is an apocalyptic number.

It is an amenable number.

65661901 is a deficient number, since it is larger than the sum of its proper divisors (1).

65661901 is an equidigital number, since it uses as much as digits as its factorization.

65661901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 65661901 is about 8103.2031320954. The cubic root of 65661901 is about 403.4327500454.

The spelling of 65661901 in words is "sixty-five million, six hundred sixty-one thousand, nine hundred one".