65640023 has 4 divisors (see below), whose sum is σ = 66878568. Its totient is φ = 64401480.

The previous prime is 65640019. The next prime is 65640049. The reversal of 65640023 is 32004656.

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 65640023 - 2² = 65640019 is a prime.

It is a super-2 number, since 2×65640023² = 8617225238881058, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65639974 and 65640001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65640083) 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, 619193 + ... + 619298.

It is an arithmetic number, because the mean of its divisors is an integer number (16719642).

Almost surely, 2^65640023 is an apocalyptic number.

65640023 is a deficient number, since it is larger than the sum of its proper divisors (1238545).

65640023 is a wasteful number, since it uses less digits than its factorization.

65640023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1238544.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 65640023 is about 8101.8530596401. The cubic root of 65640023 is about 403.3879382543.

Adding to 65640023 its reverse (32004656), we get a palindrome (97644679).

The spelling of 65640023 in words is "sixty-five million, six hundred forty thousand, twenty-three".