840451421 has 2 divisors, whose sum is σ = 840451422. Its totient is φ = 840451420.

The previous prime is 840451373. The next prime is 840451427. The reversal of 840451421 is 124154048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 686964100 + 153487321 = 26210^2 + 12389^2 .

It is a cyclic number.

It is not a de Polignac number, because 840451421 - 2⁶ = 840451357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840451427) 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, 420225710 + 420225711.

It is an arithmetic number, because the mean of its divisors is an integer number (420225711).

Almost surely, 2^840451421 is an apocalyptic number.

It is an amenable number.

840451421 is a deficient number, since it is larger than the sum of its proper divisors (1).

840451421 is an equidigital number, since it uses as much as digits as its factorization.

840451421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5120, while the sum is 29.

The square root of 840451421 is about 28990.5401984854. The cubic root of 840451421 is about 943.7077869165.

The spelling of 840451421 in words is "eight hundred forty million, four hundred fifty-one thousand, four hundred twenty-one".