7721506 has 8 divisors (see below), whose sum is σ = 12473244. Its totient is φ = 3563760.

The previous prime is 7721501. The next prime is 7721521. The reversal of 7721506 is 6051277.

It can be written as a sum of positive squares in 2 ways, for example, as 5803281 + 1918225 = 2409^2 + 1385^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (7721501) 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 3 ways as a sum of consecutive naturals, for example, 148465 + ... + 148516.

Almost surely, 2^7721506 is an apocalyptic number.

7721506 is a deficient number, since it is larger than the sum of its proper divisors (4751738).

7721506 is a wasteful number, since it uses less digits than its factorization.

7721506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296996.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 7721506 is about 2778.7597953044. The cubic root of 7721506 is about 197.6517532600.

It can be divided in two parts, 772 and 1506, that added together give a triangular number (2278 = T₆₇).

The spelling of 7721506 in words is "seven million, seven hundred twenty-one thousand, five hundred six".