65221520 has 240 divisors, whose sum is σ = 204653568. Its totient is φ = 18800640.

The previous prime is 65221517. The next prime is 65221553. The reversal of 65221520 is 2512256.

65221520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×65221520² = 8507693342220800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2103905 + ... + 2103935.

Almost surely, 2^65221520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65221520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102326784).

65221520 is an abundant number, since it is smaller than the sum of its proper divisors (139432048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65221520 is a wasteful number, since it uses less digits than its factorization.

65221520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 65221520 is about 8075.9841505540. The cubic root of 65221520 is about 402.5288124122.

Adding to 65221520 its reverse (2512256), we get a palindrome (67733776).

The spelling of 65221520 in words is "sixty-five million, two hundred twenty-one thousand, five hundred twenty".