65251621 has 16 divisors (see below), whose sum is σ = 70824960. Its totient is φ = 60052080.

The previous prime is 65251607. The next prime is 65251673. The reversal of 65251621 is 12615256.

It is not a de Polignac number, because 65251621 - 2²⁵ = 31697189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65251621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65251601) 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, 377091 + ... + 377263.

It is an arithmetic number, because the mean of its divisors is an integer number (4426560).

Almost surely, 2^65251621 is an apocalyptic number.

It is an amenable number.

65251621 is a deficient number, since it is larger than the sum of its proper divisors (5573339).

65251621 is an equidigital number, since it uses as much as digits as its factorization.

65251621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273 (or 227 counting only the distinct ones).

The product of its digits is 3600, while the sum is 28.

The square root of 65251621 is about 8077.8475474597. The cubic root of 65251621 is about 402.5907278467.

Adding to 65251621 its reverse (12615256), we get a palindrome (77866877).

The spelling of 65251621 in words is "sixty-five million, two hundred fifty-one thousand, six hundred twenty-one".