1221010001 has 4 divisors (see below), whose sum is σ = 1221463104. Its totient is φ = 1220556900.

The previous prime is 1221009973. The next prime is 1221010013. The reversal of 1221010001 is 1000101221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221010001 - 2²² = 1216815697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221010081) 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, 222485 + ... + 227906.

It is an arithmetic number, because the mean of its divisors is an integer number (305365776).

Almost surely, 2^1221010001 is an apocalyptic number.

It is an amenable number.

1221010001 is a deficient number, since it is larger than the sum of its proper divisors (453103).

1221010001 is an equidigital number, since it uses as much as digits as its factorization.

1221010001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453102.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1221010001 is about 34942.9535242801. The cubic root of 1221010001 is about 1068.8245166014.

Adding to 1221010001 its reverse (1000101221), we get a palindrome (2221111222).

The spelling of 1221010001 in words is "one billion, two hundred twenty-one million, ten thousand, one".