65691621 has 32 divisors (see below), whose sum is σ = 103783680. Its totient is φ = 40923648.

The previous prime is 65691617. The next prime is 65691629. The reversal of 65691621 is 12619656.

It is not a de Polignac number, because 65691621 - 2² = 65691617 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65691629) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 76225 + ... + 77081.

It is an arithmetic number, because the mean of its divisors is an integer number (3243240).

Almost surely, 2^65691621 is an apocalyptic number.

It is an amenable number.

65691621 is a deficient number, since it is larger than the sum of its proper divisors (38092059).

65691621 is a wasteful number, since it uses less digits than its factorization.

65691621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050 (or 1044 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 65691621 is about 8105.0367673441. The cubic root of 65691621 is about 403.4936083342.

The spelling of 65691621 in words is "sixty-five million, six hundred ninety-one thousand, six hundred twenty-one".