420517781 has 2 divisors, whose sum is σ = 420517782. Its totient is φ = 420517780.

The previous prime is 420517753. The next prime is 420517787. The reversal of 420517781 is 187715024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 397803025 + 22714756 = 19945^2 + 4766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-420517781 is a prime.

It is a super-2 number, since 2×420517781² = 353670408274327922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420517787) 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 as a sum of consecutive naturals, namely, 210258890 + 210258891.

It is an arithmetic number, because the mean of its divisors is an integer number (210258891).

Almost surely, 2^420517781 is an apocalyptic number.

It is an amenable number.

420517781 is a deficient number, since it is larger than the sum of its proper divisors (1).

420517781 is an equidigital number, since it uses as much as digits as its factorization.

420517781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15680, while the sum is 35.

The square root of 420517781 is about 20506.5302038156. The cubic root of 420517781 is about 749.1948580453.

The spelling of 420517781 in words is "four hundred twenty million, five hundred seventeen thousand, seven hundred eighty-one".