420640581 has 16 divisors (see below), whose sum is σ = 580321280. Its totient is φ = 270736560.

The previous prime is 420640573. The next prime is 420640589. The reversal of 420640581 is 185046024.

It is an interprime number because it is at equal distance from previous prime (420640573) and next prime (420640589).

It is not a de Polignac number, because 420640581 - 2³ = 420640573 is a prime.

It is a super-2 number, since 2×420640581² = 353876996768035122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420640589) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35676 + ... + 45978.

It is an arithmetic number, because the mean of its divisors is an integer number (36270080).

Almost surely, 2^420640581 is an apocalyptic number.

It is an amenable number.

420640581 is a deficient number, since it is larger than the sum of its proper divisors (159680699).

420640581 is a wasteful number, since it uses less digits than its factorization.

420640581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10776.

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 420640581 is about 20509.5241534269. The cubic root of 420640581 is about 749.2677778113.

The spelling of 420640581 in words is "four hundred twenty million, six hundred forty thousand, five hundred eighty-one".