1221650 has 24 divisors (see below), whose sum is σ = 2320164. Its totient is φ = 478400.

The previous prime is 1221641. The next prime is 1221653. The reversal of 1221650 is 561221.

It can be written as a sum of positive squares in 6 ways, for example, as 466489 + 755161 = 683^2 + 869^2 .

It is not an unprimeable number, because it can be changed into a prime (1221653) 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 11 ways as a sum of consecutive naturals, for example, 2420 + ... + 2880.

2^1221650 is an apocalyptic number.

1221650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221650 is a deficient number, since it is larger than the sum of its proper divisors (1098514).

1221650 is a wasteful number, since it uses less digits than its factorization.

1221650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526 (or 521 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1221650 is about 1105.2827692496. The cubic root of 1221650 is about 106.9011227368.

Adding to 1221650 its reverse (561221), we get a palindrome (1782871).

The spelling of 1221650 in words is "one million, two hundred twenty-one thousand, six hundred fifty".