620981 has 2 divisors, whose sum is σ = 620982. Its totient is φ = 620980.

The previous prime is 620957. The next prime is 620999. The reversal of 620981 is 189026.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 586756 + 34225 = 766^2 + 185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-620981 is a prime.

It is a super-2 number, since 2×620981² = 771234804722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 620981.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 620981.

It is not a weakly prime, because it can be changed into another prime (620911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310490 + 310491.

It is an arithmetic number, because the mean of its divisors is an integer number (310491).

2⁶²⁰⁹⁸¹ is an apocalyptic number.

It is an amenable number.

620981 is a deficient number, since it is larger than the sum of its proper divisors (1).

620981 is an equidigital number, since it uses as much as digits as its factorization.

620981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 620981 is about 788.0234768076. The cubic root of 620981 is about 85.3151392824.

The spelling of 620981 in words is "six hundred twenty thousand, nine hundred eighty-one".