1221021001 has 8 divisors (see below), whose sum is σ = 1237731264. Its totient is φ = 1204422960.

The previous prime is 1221020981. The next prime is 1221021007. The reversal of 1221021001 is 1001201221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221021001 - 2⁷ = 1221020873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221021007) 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, 6030 + ... + 49783.

It is an arithmetic number, because the mean of its divisors is an integer number (154716408).

Almost surely, 2^1221021001 is an apocalyptic number.

It is an amenable number.

1221021001 is a deficient number, since it is larger than the sum of its proper divisors (16710263).

1221021001 is a wasteful number, since it uses less digits than its factorization.

1221021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56111.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1221021001 is about 34943.1109233279. The cubic root of 1221021001 is about 1068.8277262487.

Adding to 1221021001 its reverse (1001201221), we get a palindrome (2222222222).

The spelling of 1221021001 in words is "one billion, two hundred twenty-one million, twenty-one thousand, one".