1209978640 has 40 divisors (see below), whose sum is σ = 3029602968. Its totient is φ = 446760960.

The previous prime is 1209978619. The next prime is 1209978673. The reversal of 1209978640 is 468799021.

It can be written as a sum of positive squares in 4 ways, for example, as 51984 + 1209926656 = 228^2 + 34784^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 580681 + ... + 582760.

Almost surely, 2^1209978640 is an apocalyptic number.

1209978640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1209978640 is an abundant number, since it is smaller than the sum of its proper divisors (1819624328).

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

1209978640 is a wasteful number, since it uses less digits than its factorization.

1209978640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1163467 (or 1163461 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 1209978640 is about 34784.7472320844. The cubic root of 1209978640 is about 1065.5959664091.

The spelling of 1209978640 in words is "one billion, two hundred nine million, nine hundred seventy-eight thousand, six hundred forty".