620406421 has 2 divisors, whose sum is σ = 620406422. Its totient is φ = 620406420.

The previous prime is 620406403. The next prime is 620406427. The reversal of 620406421 is 124604026.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 453221521 + 167184900 = 21289^2 + 12930^2 .

It is a cyclic number.

It is not a de Polignac number, because 620406421 - 2¹¹ = 620404373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620406427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310203210 + 310203211.

It is an arithmetic number, because the mean of its divisors is an integer number (310203211).

Almost surely, 2^620406421 is an apocalyptic number.

It is an amenable number.

620406421 is a deficient number, since it is larger than the sum of its proper divisors (1).

620406421 is an equidigital number, since it uses as much as digits as its factorization.

620406421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 620406421 is about 24907.9589890461. The cubic root of 620406421 is about 852.8881780385. Note that the first 3 decimals are identical.

The spelling of 620406421 in words is "six hundred twenty million, four hundred six thousand, four hundred twenty-one".