7812121 has 2 divisors, whose sum is σ = 7812122. Its totient is φ = 7812120.

The previous prime is 7812113. The next prime is 7812127. The reversal of 7812121 is 1212187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7371225 + 440896 = 2715^2 + 664^2 .

It is an emirp because it is prime and its reverse (1212187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7812121 - 2³ = 7812113 is a prime.

It is a super-2 number, since 2×7812121² = 122058469037282, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 7812092 and 7812101.

It is not a weakly prime, because it can be changed into another prime (7812127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3906060 + 3906061.

It is an arithmetic number, because the mean of its divisors is an integer number (3906061).

Almost surely, 2^7812121 is an apocalyptic number.

It is an amenable number.

7812121 is a deficient number, since it is larger than the sum of its proper divisors (1).

7812121 is an equidigital number, since it uses as much as digits as its factorization.

7812121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 224, while the sum is 22.

The square root of 7812121 is about 2795.0171734714. The cubic root of 7812121 is about 198.4219227775.

The spelling of 7812121 in words is "seven million, eight hundred twelve thousand, one hundred twenty-one".