620639 has 2 divisors, whose sum is σ = 620640. Its totient is φ = 620638.

The previous prime is 620623. The next prime is 620647. The reversal of 620639 is 936026.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 620639 - 2⁴ = 620623 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310319 + 310320.

It is an arithmetic number, because the mean of its divisors is an integer number (310320).

2⁶²⁰⁶³⁹ is an apocalyptic number.

620639 is a deficient number, since it is larger than the sum of its proper divisors (1).

620639 is an equidigital number, since it uses as much as digits as its factorization.

620639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 26.

The square root of 620639 is about 787.8064483108. The cubic root of 620639 is about 85.2994742107.

The spelling of 620639 in words is "six hundred twenty thousand, six hundred thirty-nine".