65521831 has 4 divisors (see below), whose sum is σ = 66170664. Its totient is φ = 64873000.

The previous prime is 65521811. The next prime is 65521837. The reversal of 65521831 is 13812556.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 65521831 - 2¹⁵ = 65489063 is a prime.

It is a super-2 number, since 2×65521831² = 8586220675185122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65521793 and 65521802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65521837) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 324265 + ... + 324466.

It is an arithmetic number, because the mean of its divisors is an integer number (16542666).

Almost surely, 2^65521831 is an apocalyptic number.

65521831 is a deficient number, since it is larger than the sum of its proper divisors (648833).

65521831 is a wasteful number, since it uses less digits than its factorization.

65521831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648832.

The product of its digits is 7200, while the sum is 31.

The square root of 65521831 is about 8094.5556394406. Note that the first 3 decimals coincide. The cubic root of 65521831 is about 403.1456781733.

The spelling of 65521831 in words is "sixty-five million, five hundred twenty-one thousand, eight hundred thirty-one".