7216661 has 2 divisors, whose sum is σ = 7216662. Its totient is φ = 7216660.

The previous prime is 7216633. The next prime is 7216663. The reversal of 7216661 is 1666127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7187761 + 28900 = 2681^2 + 170^2 .

It is an emirp because it is prime and its reverse (1666127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7216661 - 2⁶ = 7216597 is a prime.

Together with 7216663, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p₄₉₀₃₇₆ and since 7216661 and 490376 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7216663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3608330 + 3608331.

It is an arithmetic number, because the mean of its divisors is an integer number (3608331).

Almost surely, 2^7216661 is an apocalyptic number.

It is an amenable number.

7216661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7216661 is an equidigital number, since it uses as much as digits as its factorization.

7216661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 7216661 is about 2686.3843730933. The cubic root of 7216661 is about 193.2467067983.

It can be divided in two parts, 72166 and 61, that added together give a palindrome (72227).

The spelling of 7216661 in words is "seven million, two hundred sixteen thousand, six hundred sixty-one".