621681667 has 2 divisors, whose sum is σ = 621681668. Its totient is φ = 621681666.

The previous prime is 621681649. The next prime is 621681701. The reversal of 621681667 is 766186126.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621681667 is a prime.

It is not a weakly prime, because it can be changed into another prime (621681607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310840833 + 310840834.

It is an arithmetic number, because the mean of its divisors is an integer number (310840834).

Almost surely, 2^621681667 is an apocalyptic number.

621681667 is a deficient number, since it is larger than the sum of its proper divisors (1).

621681667 is an equidigital number, since it uses as much as digits as its factorization.

621681667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 621681667 is about 24933.5450146986. The cubic root of 621681667 is about 853.4721489292.

The spelling of 621681667 in words is "six hundred twenty-one million, six hundred eighty-one thousand, six hundred sixty-seven".