1211742720 has 320 divisors, whose sum is σ = 4407575040. Its totient is φ = 315408384.

The previous prime is 1211742703. The next prime is 1211742739. The reversal of 1211742720 is 272471121.

It is a happy number.

1211742720 is a `hidden beast` number, since 1 + 211 + 7 + 427 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3248454 + ... + 3248826.

It is an arithmetic number, because the mean of its divisors is an integer number (13773672).

Almost surely, 2^1211742720 is an apocalyptic number.

1211742720 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 1211742720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2203787520).

1211742720 is an abundant number, since it is smaller than the sum of its proper divisors (3195832320).

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

1211742720 is an equidigital number, since it uses as much as digits as its factorization.

1211742720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 1211742720 is about 34810.0950874886. The cubic root of 1211742720 is about 1066.1135743690.

The spelling of 1211742720 in words is "one billion, two hundred eleven million, seven hundred forty-two thousand, seven hundred twenty".