6721956 has 36 divisors (see below), whose sum is σ = 17275804. Its totient is φ = 2203200.

The previous prime is 6721951. The next prime is 6721961. The reversal of 6721956 is 6591276.

It is an interprime number because it is at equal distance from previous prime (6721951) and next prime (6721961).

It can be written as a sum of positive squares in 2 ways, for example, as 3240000 + 3481956 = 1800^2 + 1866^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 6721956.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6721951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 666 + ... + 3726.

Almost surely, 2^6721956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6721956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8637902).

6721956 is an abundant number, since it is smaller than the sum of its proper divisors (10553848).

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

6721956 is a wasteful number, since it uses less digits than its factorization.

6721956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3132 (or 3127 counting only the distinct ones).

The product of its digits is 22680, while the sum is 36.

The square root of 6721956 is about 2592.6735236045. The cubic root of 6721956 is about 188.7260665822.

It can be divided in two parts, 672 and 1956, that added together give a triangular number (2628 = T₇₂).

The spelling of 6721956 in words is "six million, seven hundred twenty-one thousand, nine hundred fifty-six".