420401665 has 4 divisors (see below), whose sum is σ = 504482004. Its totient is φ = 336321328.

The previous prime is 420401627. The next prime is 420401677. The reversal of 420401665 is 566104024.

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 72318016 + 348083649 = 8504^2 + 18657^2 .

It is a cyclic number.

It is not a de Polignac number, because 420401665 - 2¹³ = 420393473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42040162 + ... + 42040171.

It is an arithmetic number, because the mean of its divisors is an integer number (126120501).

Almost surely, 2^420401665 is an apocalyptic number.

It is an amenable number.

420401665 is a deficient number, since it is larger than the sum of its proper divisors (84080339).

420401665 is an equidigital number, since it uses as much as digits as its factorization.

420401665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84080338.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 420401665 is about 20503.6988126533. The cubic root of 420401665 is about 749.1258942405.

Adding to 420401665 its reverse (566104024), we get a palindrome (986505689).

The spelling of 420401665 in words is "four hundred twenty million, four hundred one thousand, six hundred sixty-five".