7215661 has 2 divisors, whose sum is σ = 7215662. Its totient is φ = 7215660.

The previous prime is 7215647. The next prime is 7215671. The reversal of 7215661 is 1665127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6734025 + 481636 = 2595^2 + 694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7215661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7215601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3607830 + 3607831.

It is an arithmetic number, because the mean of its divisors is an integer number (3607831).

Almost surely, 2^7215661 is an apocalyptic number.

It is an amenable number.

7215661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7215661 is an equidigital number, since it uses as much as digits as its factorization.

7215661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 28.

The square root of 7215661 is about 2686.1982428704. The cubic root of 7215661 is about 193.2377804341.

The spelling of 7215661 in words is "seven million, two hundred fifteen thousand, six hundred sixty-one".