428440781 has 2 divisors, whose sum is σ = 428440782. Its totient is φ = 428440780.

The previous prime is 428440763. The next prime is 428440799. The reversal of 428440781 is 187044824.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (428440763) and next prime (428440799).

It can be written as a sum of positive squares in only one way, i.e., 427083556 + 1357225 = 20666^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 428440781 - 2¹⁸ = 428178637 is a prime.

It is a super-2 number, since 2×428440781² = 367123005647779922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428440381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214220390 + 214220391.

It is an arithmetic number, because the mean of its divisors is an integer number (214220391).

Almost surely, 2^428440781 is an apocalyptic number.

It is an amenable number.

428440781 is a deficient number, since it is larger than the sum of its proper divisors (1).

428440781 is an equidigital number, since it uses as much as digits as its factorization.

428440781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57344, while the sum is 38.

The square root of 428440781 is about 20698.8111011237. The cubic root of 428440781 is about 753.8708211412.

The spelling of 428440781 in words is "four hundred twenty-eight million, four hundred forty thousand, seven hundred eighty-one".