1999221379 has 4 divisors (see below), whose sum is σ = 2001161520. Its totient is φ = 1997281240.

The previous prime is 1999221361. The next prime is 1999221383. The reversal of 1999221379 is 9731229991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9731229991 = 7 ⋅1390175713.

It is a cyclic number.

It is not a de Polignac number, because 1999221379 - 2¹¹ = 1999219331 is a prime.

It is a super-2 number, since 2×1999221379² = 7993772244501323282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999221079) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 968524 + ... + 970585.

It is an arithmetic number, because the mean of its divisors is an integer number (500290380).

Almost surely, 2^1999221379 is an apocalyptic number.

1999221379 is a deficient number, since it is larger than the sum of its proper divisors (1940141).

1999221379 is a wasteful number, since it uses less digits than its factorization.

1999221379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1940140.

The product of its digits is 551124, while the sum is 52.

The square root of 1999221379 is about 44712.6534551462. The cubic root of 1999221379 is about 1259.7575285082.

The spelling of 1999221379 in words is "one billion, nine hundred ninety-nine million, two hundred twenty-one thousand, three hundred seventy-nine".