65040021 has 36 divisors (see below), whose sum is σ = 103521600. Its totient is φ = 39237264.

The previous prime is 65040013. The next prime is 65040029. The reversal of 65040021 is 12004056.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (65040013) and next prime (65040029).

It is not a de Polignac number, because 65040021 - 2³ = 65040013 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 65039976 and 65040003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65040029) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 90100 + ... + 90818.

It is an arithmetic number, because the mean of its divisors is an integer number (2875600).

Almost surely, 2^65040021 is an apocalyptic number.

It is an amenable number.

65040021 is a deficient number, since it is larger than the sum of its proper divisors (38481579).

65040021 is a wasteful number, since it uses less digits than its factorization.

65040021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790 (or 764 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 65040021 is about 8064.7393634264. The cubic root of 65040021 is about 402.1550786546.

Adding to 65040021 its reverse (12004056), we get a palindrome (77044077).

The spelling of 65040021 in words is "sixty-five million, forty thousand, twenty-one".