65447721 has 6 divisors (see below), whose sum is σ = 94535610. Its totient is φ = 43631808.

The previous prime is 65447713. The next prime is 65447737. The reversal of 65447721 is 12774456.

It can be written as a sum of positive squares in only one way, i.e., 63920025 + 1527696 = 7995^2 + 1236^2 .

It is not a de Polignac number, because 65447721 - 2³ = 65447713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (65447791) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3635976 + ... + 3635993.

It is an arithmetic number, because the mean of its divisors is an integer number (15755935).

Almost surely, 2^65447721 is an apocalyptic number.

It is an amenable number.

65447721 is a deficient number, since it is larger than the sum of its proper divisors (29087889).

65447721 is a wasteful number, since it uses less digits than its factorization.

65447721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7271975 (or 7271972 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The square root of 65447721 is about 8089.9765759859. The cubic root of 65447721 is about 402.9936250472.

The spelling of 65447721 in words is "sixty-five million, four hundred forty-seven thousand, seven hundred twenty-one".