620632781 has 2 divisors, whose sum is σ = 620632782. Its totient is φ = 620632780.

The previous prime is 620632757. The next prime is 620632813. The reversal of 620632781 is 187236026.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 536617225 + 84015556 = 23165^2 + 9166^2 .

It is a cyclic number.

It is not a de Polignac number, because 620632781 - 2¹⁸ = 620370637 is a prime.

It is a super-2 number, since 2×620632781² = 770370097703587922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620632711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310316390 + 310316391.

It is an arithmetic number, because the mean of its divisors is an integer number (310316391).

Almost surely, 2^620632781 is an apocalyptic number.

It is an amenable number.

620632781 is a deficient number, since it is larger than the sum of its proper divisors (1).

620632781 is an equidigital number, since it uses as much as digits as its factorization.

620632781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 620632781 is about 24912.5025037630. The cubic root of 620632781 is about 852.9918930047.

The spelling of 620632781 in words is "six hundred twenty million, six hundred thirty-two thousand, seven hundred eighty-one".