1020001221 has 16 divisors (see below), whose sum is σ = 1512345600. Its totient is φ = 679446144.

The previous prime is 1020001201. The next prime is 1020001223. The reversal of 1020001221 is 1221000201.

It is not a de Polignac number, because 1020001221 - 2⁵ = 1020001189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

1020001221 is a modest number, since divided by 1221 gives 1020 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020001223) 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, 19765 + ... + 49301.

It is an arithmetic number, because the mean of its divisors is an integer number (94521600).

Almost surely, 2^1020001221 is an apocalyptic number.

It is an amenable number.

1020001221 is a deficient number, since it is larger than the sum of its proper divisors (492344379).

1020001221 is a wasteful number, since it uses less digits than its factorization.

1020001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30825 (or 30819 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1020001221 is about 31937.4579608334. The cubic root of 1020001221 is about 1006.6231112222.

Adding to 1020001221 its reverse (1221000201), we get a palindrome (2241001422).

The spelling of 1020001221 in words is "one billion, twenty million, one thousand, two hundred twenty-one".