1211001000 has 128 divisors (see below), whose sum is σ = 4121919360. Its totient is φ = 293568000.

The previous prime is 1211000971. The next prime is 1211001023. The reversal of 1211001000 is 1001121.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1211001000.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14652 + ... + 51348.

It is an arithmetic number, because the mean of its divisors is an integer number (32202495).

Almost surely, 2^1211001000 is an apocalyptic number.

1211001000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2060959680).

1211001000 is an abundant number, since it is smaller than the sum of its proper divisors (2910918360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211001000 is a wasteful number, since it uses less digits than its factorization.

1211001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36732 (or 36718 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 6.

The square root of 1211001000 is about 34799.4396506610. The cubic root of 1211001000 is about 1065.8960036626.

Adding to 1211001000 its reverse (1001121), we get a palindrome (1212002121).

The spelling of 1211001000 in words is "one billion, two hundred eleven million, one thousand".