420021855 has 72 divisors (see below), whose sum is σ = 830168976. Its totient is φ = 203575680.

The previous prime is 420021853. The next prime is 420021857. The reversal of 420021855 is 558120024.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (420021853) and next prime (420021857).

It is not a de Polignac number, because 420021855 - 2¹ = 420021853 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420021851) 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 71 ways as a sum of consecutive naturals, for example, 145587 + ... + 148443.

Almost surely, 2^420021855 is an apocalyptic number.

420021855 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

420021855 is a deficient number, since it is larger than the sum of its proper divisors (410147121).

420021855 is a wasteful number, since it uses less digits than its factorization.

420021855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2899 (or 2876 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 420021855 is about 20494.4347323853. The cubic root of 420021855 is about 748.9002281240.

Adding to 420021855 its reverse (558120024), we get a palindrome (978141879).

The spelling of 420021855 in words is "four hundred twenty million, twenty-one thousand, eight hundred fifty-five".