65216391 has 8 divisors (see below), whose sum is σ = 86993664. Its totient is φ = 43458360.

The previous prime is 65216357. The next prime is 65216399. The reversal of 65216391 is 19361256.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65216391 - 2²¹ = 63119239 is a prime.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65216399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7900 + ... + 13886.

It is an arithmetic number, because the mean of its divisors is an integer number (10874208).

Almost surely, 2^65216391 is an apocalyptic number.

65216391 is the 5108-th centered pentagonal number.

65216391 is a deficient number, since it is larger than the sum of its proper divisors (21777273).

65216391 is a wasteful number, since it uses less digits than its factorization.

65216391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9621.

The product of its digits is 9720, while the sum is 33.

The square root of 65216391 is about 8075.6665978729. Note that the first 3 decimals coincide. The cubic root of 65216391 is about 402.5182605555.

The spelling of 65216391 in words is "sixty-five million, two hundred sixteen thousand, three hundred ninety-one".