1209945680 has 30 divisors (see below), whose sum is σ = 2813847246. Its totient is φ = 483853824.

The previous prime is 1209945673. The next prime is 1209945691. The reversal of 1209945680 is 865499021.

It can be written as a sum of positive squares in 3 ways, for example, as 335915584 + 874030096 = 18328^2 + 29564^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 309176 + ... + 313064.

Almost surely, 2^1209945680 is an apocalyptic number.

1209945680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1209945680 is an abundant number, since it is smaller than the sum of its proper divisors (1603901566).

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

1209945680 is an frugal number, since it uses more digits than its factorization.

1209945680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7791 (or 3896 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 1209945680 is about 34784.2734579867. The cubic root of 1209945680 is about 1065.5862906565.

The spelling of 1209945680 in words is "one billion, two hundred nine million, nine hundred forty-five thousand, six hundred eighty".