1001011221 has 48 divisors (see below), whose sum is σ = 1825784064. Its totient is φ = 514939392.

The previous prime is 1001011211. The next prime is 1001011229. The reversal of 1001011221 is 1221101001.

It is a happy number.

1001011221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1001011221 - 2⁶ = 1001011157 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001011229) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4315 + ... + 44951.

It is an arithmetic number, because the mean of its divisors is an integer number (38037168).

Almost surely, 2^1001011221 is an apocalyptic number.

It is an amenable number.

1001011221 is a deficient number, since it is larger than the sum of its proper divisors (824772843).

1001011221 is a wasteful number, since it uses less digits than its factorization.

1001011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40690 (or 40687 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1001011221 is about 31638.7613695606. The cubic root of 1001011221 is about 1000.3369601118.

Adding to 1001011221 its reverse (1221101001), we get a palindrome (2222112222).

The spelling of 1001011221 in words is "one billion, one million, eleven thousand, two hundred twenty-one".