1221698 has 4 divisors (see below), whose sum is σ = 1832550. Its totient is φ = 610848.

The previous prime is 1221667. The next prime is 1221707. The reversal of 1221698 is 8961221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 833569 + 388129 = 913^2 + 623^2 .

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221698.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 305423 + ... + 305426.

2^1221698 is an apocalyptic number.

1221698 is a deficient number, since it is larger than the sum of its proper divisors (610852).

1221698 is an equidigital number, since it uses as much as digits as its factorization.

1221698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610851.

The product of its digits is 1728, while the sum is 29.

The square root of 1221698 is about 1105.3044829367. The cubic root of 1221698 is about 106.9025228069.

It can be divided in two parts, 1221 and 698, that multiplied together give a palindrome (852258).

The spelling of 1221698 in words is "one million, two hundred twenty-one thousand, six hundred ninety-eight".