1211128640 has 28 divisors (see below), whose sum is σ = 2884000836. Its totient is φ = 484451328.

The previous prime is 1211128621. The next prime is 1211128651. The reversal of 1211128640 is 468211121.

It can be written as a sum of positive squares in 2 ways, for example, as 335915584 + 875213056 = 18328^2 + 29584^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1892069 + ... + 1892708.

Almost surely, 2^1211128640 is an apocalyptic number.

1211128640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211128640 is an abundant number, since it is smaller than the sum of its proper divisors (1672872196).

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

1211128640 is an equidigital number, since it uses as much as digits as its factorization.

1211128640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3784794 (or 3784784 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 1211128640 is about 34801.2735399152. The cubic root of 1211128640 is about 1065.9334509717.

Adding to 1211128640 its reverse (468211121), we get a palindrome (1679339761).

The spelling of 1211128640 in words is "one billion, two hundred eleven million, one hundred twenty-eight thousand, six hundred forty".