2197681 has 2 divisors, whose sum is σ = 2197682. Its totient is φ = 2197680.

The previous prime is 2197651. The next prime is 2197693. The reversal of 2197681 is 1867912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2117025 + 80656 = 1455^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 2197681 - 2¹⁷ = 2066609 is a prime.

It is a super-2 number, since 2×2197681² = 9659603555522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2197631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1098840 + 1098841.

It is an arithmetic number, because the mean of its divisors is an integer number (1098841).

2^2197681 is an apocalyptic number.

It is an amenable number.

2197681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2197681 is an equidigital number, since it uses as much as digits as its factorization.

2197681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 34.

The square root of 2197681 is about 1482.4577565651. The cubic root of 2197681 is about 130.0134305651.

The spelling of 2197681 in words is "two million, one hundred ninety-seven thousand, six hundred eighty-one".