421820657 has 2 divisors, whose sum is σ = 421820658. Its totient is φ = 421820656.

The previous prime is 421820647. The next prime is 421820687. The reversal of 421820657 is 756028124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 413064976 + 8755681 = 20324^2 + 2959^2 .

It is a cyclic number.

It is not a de Polignac number, because 421820657 - 2⁶ = 421820593 is a prime.

It is not a weakly prime, because it can be changed into another prime (421820647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210910328 + 210910329.

It is an arithmetic number, because the mean of its divisors is an integer number (210910329).

Almost surely, 2^421820657 is an apocalyptic number.

It is an amenable number.

421820657 is a deficient number, since it is larger than the sum of its proper divisors (1).

421820657 is an equidigital number, since it uses as much as digits as its factorization.

421820657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 421820657 is about 20538.2729799757. The cubic root of 421820657 is about 749.9677953579.

The spelling of 421820657 in words is "four hundred twenty-one million, eight hundred twenty thousand, six hundred fifty-seven".