7816121 has 2 divisors, whose sum is σ = 7816122. Its totient is φ = 7816120.

The previous prime is 7816111. The next prime is 7816157. The reversal of 7816121 is 1216187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7812025 + 4096 = 2795^2 + 64^2 .

It is a cyclic number.

It is not a de Polignac number, because 7816121 - 2⁶ = 7816057 is a prime.

It is a super-2 number, since 2×7816121² = 122183494973282, which contains 22 as substring.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is equal to p₅₂₈₁₉₁ and since 7816121 and 528191 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (7816111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3908060 + 3908061.

It is an arithmetic number, because the mean of its divisors is an integer number (3908061).

Almost surely, 2^7816121 is an apocalyptic number.

It is an amenable number.

7816121 is a deficient number, since it is larger than the sum of its proper divisors (1).

7816121 is an equidigital number, since it uses as much as digits as its factorization.

7816121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 26.

The square root of 7816121 is about 2795.7326410084. The cubic root of 7816121 is about 198.4557826501.

The spelling of 7816121 in words is "seven million, eight hundred sixteen thousand, one hundred twenty-one".