620705639 has 2 divisors, whose sum is σ = 620705640. Its totient is φ = 620705638.

The previous prime is 620705633. The next prime is 620705651. The reversal of 620705639 is 936507026.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-620705639 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620705633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310352819 + 310352820.

It is an arithmetic number, because the mean of its divisors is an integer number (310352820).

Almost surely, 2^620705639 is an apocalyptic number.

620705639 is a deficient number, since it is larger than the sum of its proper divisors (1).

620705639 is an equidigital number, since it uses as much as digits as its factorization.

620705639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 38.

The square root of 620705639 is about 24913.9647386762. The cubic root of 620705639 is about 853.0252701501.

The spelling of 620705639 in words is "six hundred twenty million, seven hundred five thousand, six hundred thirty-nine".