1221697 has 4 divisors (see below), whose sum is σ = 1238976. Its totient is φ = 1204420.

The previous prime is 1221667. The next prime is 1221707. The reversal of 1221697 is 7961221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7961221 = 347 ⋅22943.

It is a cyclic number.

It is not a de Polignac number, because 1221697 - 2¹¹ = 1219649 is a prime.

It is a Duffinian number.

1221697 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1221667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8533 + ... + 8674.

It is an arithmetic number, because the mean of its divisors is an integer number (309744).

2^1221697 is an apocalyptic number.

It is an amenable number.

1221697 is a deficient number, since it is larger than the sum of its proper divisors (17279).

1221697 is an equidigital number, since it uses as much as digits as its factorization.

1221697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17278.

The product of its digits is 1512, while the sum is 28.

The square root of 1221697 is about 1105.3040305726. The cubic root of 1221697 is about 106.9024936391.

The spelling of 1221697 in words is "one million, two hundred twenty-one thousand, six hundred ninety-seven".