1221739019 has 4 divisors (see below), whose sum is σ = 1242446520. Its totient is φ = 1201031520.

The previous prime is 1221739003. The next prime is 1221739027. The reversal of 1221739019 is 9109371221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221739019 - 2⁴ = 1221739003 is a prime.

It is a super-2 number, since 2×1221739019² = 2985292461094164722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221739019.

It is not an unprimeable number, because it can be changed into a prime (1221739039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10353662 + ... + 10353779.

It is an arithmetic number, because the mean of its divisors is an integer number (310611630).

Almost surely, 2^1221739019 is an apocalyptic number.

1221739019 is a deficient number, since it is larger than the sum of its proper divisors (20707501).

1221739019 is an equidigital number, since it uses as much as digits as its factorization.

1221739019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20707500.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 1221739019 is about 34953.3835129019. The cubic root of 1221739019 is about 1069.0371922516.

The spelling of 1221739019 in words is "one billion, two hundred twenty-one million, seven hundred thirty-nine thousand, nineteen".