1211402220 has 96 divisors (see below), whose sum is σ = 3897040896. Its totient is φ = 275424000.

The previous prime is 1211402177. The next prime is 1211402243. The reversal of 1211402220 is 222041121.

It is a super-3 number, since 3×1211402220³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1211402220.

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, 72670 + ... + 87770.

It is an arithmetic number, because the mean of its divisors is an integer number (40594176).

Almost surely, 2^1211402220 is an apocalyptic number.

1211402220 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 1211402220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1948520448).

1211402220 is an abundant number, since it is smaller than the sum of its proper divisors (2685638676).

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

1211402220 is a wasteful number, since it uses less digits than its factorization.

1211402220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15311 (or 15309 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 1211402220 is about 34805.2039212529. The cubic root of 1211402220 is about 1066.0137056226.

Adding to 1211402220 its reverse (222041121), we get a palindrome (1433443341).

The spelling of 1211402220 in words is "one billion, two hundred eleven million, four hundred two thousand, two hundred twenty".