20987842400001 has 9 divisors (see below), whose sum is σ = 30315792207649. Its totient is φ = 13991885770836.

The previous prime is 20987842399949. The next prime is 20987842400017. The reversal of 20987842400001 is 10000424878902.

The square root of 20987842400001 is 4581249.

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

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 20987842400001 - 2¹¹ = 20987842397953 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20987842400001.

It is not an unprimeable number, because it can be changed into a prime (20987842400071) 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 8 ways as a sum of consecutive naturals, for example, 12980206 + ... + 14507288.

Almost surely, 2^{20987842400001} is an apocalyptic number.

20987842400001 is the 4581249-th square number.

20987842400001 is the 2290625-th centered octagonal number.

It is an amenable number.

20987842400001 is a deficient number, since it is larger than the sum of its proper divisors (9327949807648).

20987842400001 is an frugal number, since it uses more digits than its factorization.

20987842400001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3054172 (or 1527086 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 20987842400001 in words is "twenty trillion, nine hundred eighty-seven billion, eight hundred forty-two million, four hundred thousand, one".