621988 has 12 divisors (see below), whose sum is σ = 1097712. Its totient is φ = 308360.

The previous prime is 621983. The next prime is 621997. The reversal of 621988 is 889126.

It is not an unprimeable number, because it can be changed into a prime (621983) by changing a digit.

621988 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 3 ways as a sum of consecutive naturals, for example, 70 + ... + 1117.

It is an arithmetic number, because the mean of its divisors is an integer number (91476).

2⁶²¹⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

621988 is a deficient number, since it is larger than the sum of its proper divisors (475724).

621988 is a wasteful number, since it uses less digits than its factorization.

621988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1322 (or 1320 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 621988 is about 788.6621583416. The cubic root of 621988 is about 85.3612308418.

It can be divided in two parts, 62 and 1988, that multiplied together give a triangular number (123256 = T₄₉₆).

The spelling of 621988 in words is "six hundred twenty-one thousand, nine hundred eighty-eight".