6621940 has 24 divisors (see below), whose sum is σ = 14976360. Its totient is φ = 2444928.

The previous prime is 6621931. The next prime is 6621943. The reversal of 6621940 is 491266.

It can be written as a sum of positive squares in 4 ways, for example, as 501264 + 6120676 = 708^2 + 2474^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6621899 and 6621908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6621943) 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 in 7 ways as a sum of consecutive naturals, for example, 12475 + ... + 12994.

It is an arithmetic number, because the mean of its divisors is an integer number (624015).

Almost surely, 2^6621940 is an apocalyptic number.

It is an amenable number.

6621940 is an abundant number, since it is smaller than the sum of its proper divisors (8354420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6621940 is a wasteful number, since it uses less digits than its factorization.

6621940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25491 (or 25489 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 6621940 is about 2573.3130396436. The cubic root of 6621940 is about 187.7853669449.

The spelling of 6621940 in words is "six million, six hundred twenty-one thousand, nine hundred forty".