1219921668 has 48 divisors (see below), whose sum is σ = 3614584960. Its totient is φ = 348548832.

The previous prime is 1219921639. The next prime is 1219921669. The reversal of 1219921668 is 8661299121.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1219921669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 806071 + ... + 807582.

Almost surely, 2^1219921668 is an apocalyptic number.

1219921668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1219921668 is an abundant number, since it is smaller than the sum of its proper divisors (2394663292).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1219921668 is a wasteful number, since it uses less digits than its factorization.

1219921668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1613673 (or 1613665 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 1219921668 is about 34927.3770558283. The cubic root of 1219921668 is about 1068.5068607876.

The spelling of 1219921668 in words is "one billion, two hundred nineteen million, nine hundred twenty-one thousand, six hundred sixty-eight".