65220021 has 12 divisors (see below), whose sum is σ = 94404960. Its totient is φ = 43388520.

The previous prime is 65220017. The next prime is 65220059. The reversal of 65220021 is 12002256.

It is not a de Polignac number, because 65220021 - 2² = 65220017 is a prime.

It is a super-2 number, since 2×65220021² = 8507302278480882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 65219976 and 65220003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65225021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2961 + ... + 11798.

It is an arithmetic number, because the mean of its divisors is an integer number (7867080).

Almost surely, 2^65220021 is an apocalyptic number.

It is an amenable number.

65220021 is a deficient number, since it is larger than the sum of its proper divisors (29184939).

65220021 is a wasteful number, since it uses less digits than its factorization.

65220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15256 (or 15253 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 65220021 is about 8075.8913439942. The cubic root of 65220021 is about 402.5257285869.

Adding to 65220021 its reverse (12002256), we get a palindrome (77222277).

The spelling of 65220021 in words is "sixty-five million, two hundred twenty thousand, twenty-one".