427256821 has 4 divisors (see below), whose sum is σ = 427458892. Its totient is φ = 427054752.

The previous prime is 427256813. The next prime is 427256827. The reversal of 427256821 is 128652724.

It is a happy number.

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 18610596 + 408646225 = 4314^2 + 20215^2 .

It is a cyclic number.

It is not a de Polignac number, because 427256821 - 2³ = 427256813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (427256827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97830 + ... + 102103.

It is an arithmetic number, because the mean of its divisors is an integer number (106864723).

Almost surely, 2^427256821 is an apocalyptic number.

It is an amenable number.

427256821 is a deficient number, since it is larger than the sum of its proper divisors (202071).

427256821 is a wasteful number, since it uses less digits than its factorization.

427256821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202070.

The product of its digits is 53760, while the sum is 37.

The square root of 427256821 is about 20670.1916053045. The cubic root of 427256821 is about 753.1757610019.

The spelling of 427256821 in words is "four hundred twenty-seven million, two hundred fifty-six thousand, eight hundred twenty-one".