65651621 has 24 divisors (see below), whose sum is σ = 80766720. Its totient is φ = 53122272.

The previous prime is 65651617. The next prime is 65651639. The reversal of 65651621 is 12615656.

It is not a de Polignac number, because 65651621 - 2² = 65651617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65651611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66296 + ... + 67278.

It is an arithmetic number, because the mean of its divisors is an integer number (3365280).

Almost surely, 2^65651621 is an apocalyptic number.

It is an amenable number.

65651621 is a deficient number, since it is larger than the sum of its proper divisors (15115099).

65651621 is a wasteful number, since it uses less digits than its factorization.

65651621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073 (or 1066 counting only the distinct ones).

The product of its digits is 10800, while the sum is 32.

The square root of 65651621 is about 8102.5687902047. The cubic root of 65651621 is about 403.4116951919.

The spelling of 65651621 in words is "sixty-five million, six hundred fifty-one thousand, six hundred twenty-one".