420420551 has 2 divisors, whose sum is σ = 420420552. Its totient is φ = 420420550.

The previous prime is 420420487. The next prime is 420420577. The reversal of 420420551 is 155024024.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 420420551 - 2⁶ = 420420487 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420420851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210210275 + 210210276.

It is an arithmetic number, because the mean of its divisors is an integer number (210210276).

Almost surely, 2^420420551 is an apocalyptic number.

420420551 is a deficient number, since it is larger than the sum of its proper divisors (1).

420420551 is an equidigital number, since it uses as much as digits as its factorization.

420420551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 420420551 is about 20504.1593585302. The cubic root of 420420551 is about 749.1371119092.

Adding to 420420551 its reverse (155024024), we get a palindrome (575444575).

The spelling of 420420551 in words is "four hundred twenty million, four hundred twenty thousand, five hundred fifty-one".