20780087409 has 63 divisors (see below), whose sum is σ = 32999400219. Its totient is φ = 13077560160.

The previous prime is 20780087329. The next prime is 20780087459. The reversal of 20780087409 is 90478008702.

The square root of 20780087409 is 144153.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 14042961009 + 6737126400 = 118503^2 + 82080^2 .

It is not a de Polignac number, because 20780087409 - 2⁷ = 20780087281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20780087459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 73950349 + ... + 73950629.

Almost surely, 2^20780087409 is an apocalyptic number.

20780087409 is the 144153-rd square number.

20780087409 is the 72077-th centered octagonal number.

It is an amenable number.

20780087409 is a deficient number, since it is larger than the sum of its proper divisors (12219312810).

20780087409 is an frugal number, since it uses more digits than its factorization.

20780087409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The spelling of 20780087409 in words is "twenty billion, seven hundred eighty million, eighty-seven thousand, four hundred nine".