1001221992 has 32 divisors (see below), whose sum is σ = 2781172800. Its totient is φ = 333740592.

The previous prime is 1001221981. The next prime is 1001221999. The reversal of 1001221992 is 2991221001.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1001221999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2317428 + ... + 2317859.

It is an arithmetic number, because the mean of its divisors is an integer number (86911650).

Almost surely, 2^1001221992 is an apocalyptic number.

1001221992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1001221992 is an abundant number, since it is smaller than the sum of its proper divisors (1779950808).

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

1001221992 is a wasteful number, since it uses less digits than its factorization.

1001221992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4635302 (or 4635292 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 1001221992 is about 31642.0920926541. The cubic root of 1001221992 is about 1000.4071648609.

Adding to 1001221992 its reverse (2991221001), we get a palindrome (3992442993).

The spelling of 1001221992 in words is "one billion, one million, two hundred twenty-one thousand, nine hundred ninety-two".