420640641 has 8 divisors (see below), whose sum is σ = 623171360. Its totient is φ = 280427076.

The previous prime is 420640589. The next prime is 420640657. The reversal of 420640641 is 146046024.

It is not a de Polignac number, because 420640641 - 2¹¹ = 420638593 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 15579283 = 420640641 / (4 + 2 + 0 + 6 + 4 + 0 + 6 + 4 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (420640691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7789615 + ... + 7789668.

It is an arithmetic number, because the mean of its divisors is an integer number (77896420).

Almost surely, 2^420640641 is an apocalyptic number.

It is an amenable number.

420640641 is a deficient number, since it is larger than the sum of its proper divisors (202530719).

420640641 is a wasteful number, since it uses less digits than its factorization.

420640641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15579292 (or 15579286 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 420640641 is about 20509.5256161619. The cubic root of 420640641 is about 749.2678134364.

Adding to 420640641 its reverse (146046024), we get a palindrome (566686665).

The spelling of 420640641 in words is "four hundred twenty million, six hundred forty thousand, six hundred forty-one".