1001221987 has 8 divisors (see below), whose sum is σ = 1060495632. Its totient is φ = 941990400.

The previous prime is 1001221981. The next prime is 1001221999. The reversal of 1001221987 is 7891221001.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1001221987 - 2¹⁹ = 1000697699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1001221981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47787 + ... + 65467.

It is an arithmetic number, because the mean of its divisors is an integer number (132561954).

Almost surely, 2^1001221987 is an apocalyptic number.

1001221987 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1001221987 is a deficient number, since it is larger than the sum of its proper divisors (59273645).

1001221987 is a wasteful number, since it uses less digits than its factorization.

1001221987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21029.

The product of its (nonzero) digits is 2016, while the sum is 31.

The square root of 1001221987 is about 31642.0920136454. The cubic root of 1001221987 is about 1000.4071631956.

Adding to 1001221987 its reverse (7891221001), we get a palindrome (8892442988).

The spelling of 1001221987 in words is "one billion, one million, two hundred twenty-one thousand, nine hundred eighty-seven".