1221320019 has 32 divisors (see below), whose sum is σ = 1749786880. Its totient is φ = 755453952.

The previous prime is 1221319999. The next prime is 1221320021. The reversal of 1221320019 is 9100231221.

It is not a de Polignac number, because 1221320019 - 2¹¹ = 1221317971 is a prime.

It is a super-2 number, since 2×1221320019² = 2983245177620320722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221319977 and 1221320004.

It is not an unprimeable number, because it can be changed into a prime (1221320029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 736239 + ... + 737895.

It is an arithmetic number, because the mean of its divisors is an integer number (54680840).

Almost surely, 2^1221320019 is an apocalyptic number.

1221320019 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1221320019 is a deficient number, since it is larger than the sum of its proper divisors (528466861).

1221320019 is a wasteful number, since it uses less digits than its factorization.

1221320019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1939.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 1221320019 is about 34947.3893016345. The cubic root of 1221320019 is about 1068.9149681671.

The spelling of 1221320019 in words is "one billion, two hundred twenty-one million, three hundred twenty thousand, nineteen".