428532781 has 2 divisors, whose sum is σ = 428532782. Its totient is φ = 428532780.

The previous prime is 428532773. The next prime is 428532817. The reversal of 428532781 is 187235824.

It is a happy number.

Together with next prime (428532817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 416568100 + 11964681 = 20410^2 + 3459^2 .

It is a cyclic number.

It is not a de Polignac number, because 428532781 - 2³ = 428532773 is a prime.

It is a super-2 number, since 2×428532781² = 367280688783187922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428512781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214266390 + 214266391.

It is an arithmetic number, because the mean of its divisors is an integer number (214266391).

Almost surely, 2^428532781 is an apocalyptic number.

It is an amenable number.

428532781 is a deficient number, since it is larger than the sum of its proper divisors (1).

428532781 is an equidigital number, since it uses as much as digits as its factorization.

428532781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107520, while the sum is 40.

The square root of 428532781 is about 20701.0333316963. The cubic root of 428532781 is about 753.9247773742.

The spelling of 428532781 in words is "four hundred twenty-eight million, five hundred thirty-two thousand, seven hundred eighty-one".