65228721 has 16 divisors (see below), whose sum is σ = 90334464. Its totient is φ = 41835024.

The previous prime is 65228707. The next prime is 65228731. The reversal of 65228721 is 12782256.

It is not a de Polignac number, because 65228721 - 2⁷ = 65228593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65228701) 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, 4870 + ... + 12416.

It is an arithmetic number, because the mean of its divisors is an integer number (5645904).

Almost surely, 2^65228721 is an apocalyptic number.

It is an amenable number.

65228721 is a deficient number, since it is larger than the sum of its proper divisors (25105743).

65228721 is a wasteful number, since it uses less digits than its factorization.

65228721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7660.

The product of its digits is 13440, while the sum is 33.

The square root of 65228721 is about 8076.4299662660. The cubic root of 65228721 is about 402.5436260469.

The spelling of 65228721 in words is "sixty-five million, two hundred twenty-eight thousand, seven hundred twenty-one".