65221521 has 8 divisors (see below), whose sum is σ = 86999520. Its totient is φ = 43462272.

The previous prime is 65221517. The next prime is 65221553. The reversal of 65221521 is 12512256.

It is a happy number.

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

It is not a de Polignac number, because 65221521 - 2² = 65221517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 65221491 and 65221500.

It is not an unprimeable number, because it can be changed into a prime (65221501) 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, 10081 + ... + 15233.

It is an arithmetic number, because the mean of its divisors is an integer number (10874940).

Almost surely, 2^65221521 is an apocalyptic number.

It is an amenable number.

65221521 is a deficient number, since it is larger than the sum of its proper divisors (21777999).

65221521 is a wasteful number, since it uses less digits than its factorization.

65221521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9375.

The product of its digits is 1200, while the sum is 24.

The square root of 65221521 is about 8075.9842124660. The cubic root of 65221521 is about 402.5288144694.

Adding to 65221521 its reverse (12512256), we get a palindrome (77733777).

The spelling of 65221521 in words is "sixty-five million, two hundred twenty-one thousand, five hundred twenty-one".