20402065 has 4 divisors (see below), whose sum is σ = 24482484. Its totient is φ = 16321648.

The previous prime is 20402021. The next prime is 20402087. The reversal of 20402065 is 56020402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2483776 + 17918289 = 1576^2 + 4233^2 .

It is a cyclic number.

It is not a de Polignac number, because 20402065 - 2⁹ = 20401553 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2040202 + ... + 2040211.

It is an arithmetic number, because the mean of its divisors is an integer number (6120621).

Almost surely, 2^20402065 is an apocalyptic number.

It is an amenable number.

20402065 is a deficient number, since it is larger than the sum of its proper divisors (4080419).

20402065 is an equidigital number, since it uses as much as digits as its factorization.

20402065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080418.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20402065 is about 4516.8645098121. The cubic root of 20402065 is about 273.2486608972.

Adding to 20402065 its reverse (56020402), we get a palindrome (76422467).

The spelling of 20402065 in words is "twenty million, four hundred two thousand, sixty-five".