1212126660 has 384 divisors, whose sum is σ = 4249190400. Its totient is φ = 285534720.

The previous prime is 1212126649. The next prime is 1212126667. The reversal of 1212126660 is 666212121.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1212126667) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 11768169 + ... + 11768271.

It is an arithmetic number, because the mean of its divisors is an integer number (11065600).

Almost surely, 2^1212126660 is an apocalyptic number.

1212126660 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 1212126660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2124595200).

1212126660 is an abundant number, since it is smaller than the sum of its proper divisors (3037063740).

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

1212126660 is a wasteful number, since it uses less digits than its factorization.

1212126660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 1212126660 is about 34815.6094302541. The cubic root of 1212126660 is about 1066.2261616411.

Adding to 1212126660 its reverse (666212121), we get a palindrome (1878338781).

It can be divided in two parts, 12121 and 26660, that added together give a triangular number (38781 = T₂₇₈).

The spelling of 1212126660 in words is "one billion, two hundred twelve million, one hundred twenty-six thousand, six hundred sixty".